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<section data-tool="mdnice编辑器" data-website="https://www.mdnice.com" style="margin-bottom: 0px;padding-left: 10px;padding-right: 10px;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;width: auto;font-family: Optima, " microsoft yahei, pingfangsc-regular, serif;font-size: 16px;color: rgb(0, 0, 0);line-height: 1.5em;word-spacing: 0em;letter-spacing: 0em;word-break: break-word;text-align: left;> <h3 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;border-style: none;border-width: 1px;border-color: rgb(0, 0, 0);border-radius: 0px;box-shadow: none;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow: unset;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-left: 20px;border-style: none none none solid;border-width: 1px 1px 1px 3px;border-color: rgb(0, 0, 0) rgb(0, 0, 0) rgb(0, 0, 0) rgb(255, 177, 27);border-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;overflow: unset;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">1. 业务背景</h3> 有些业务请求，属于耗时操作，需要加锁，防止后续的并发操作，同时对数据库的数据进行操作，需要避免对之前的业务造成影响。 <h3 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;border-style: none;border-width: 1px;border-color: rgb(0, 0, 0);border-radius: 0px;box-shadow: none;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow: unset;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-left: 20px;border-style: none none none solid;border-width: 1px 1px 1px 3px;border-color: rgb(0, 0, 0) rgb(0, 0, 0) rgb(0, 0, 0) rgb(255, 177, 27);border-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;overflow: unset;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">2. 分析流程</h3> 使用 Redis 作为分布式锁，将锁的状态放到 Redis 统一维护，解决集群中单机 JVM 信息不互通的问题，规定操作顺序，保护用户的数据正确。 <strong style="color: rgb(0, 0, 0);background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;border-style: none;border-width: 3px;border-color: rgba(0, 0, 0, 0.4);border-radius: 0px;">梳理设计流程 <ul data-tool="mdnice编辑器" style="margin-top: 8px;margin-bottom: 8px;padding-left: 25px;" class="list-paddingleft-1"> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 新建注解 <code style="background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>@interface</code>，在注解里设定入参标志 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 增加 AOP 切点，扫描特定注解 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 建立 <code style="background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>@Aspect</code> 切面任务，注册 bean 和拦截特定方法 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 特定方法参数 <code style="background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>ProceedingJoinPoint</code>，对方法 <code style="background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>pjp.proceed()</code> 前后进行拦截 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 切点前进行加锁，任务执行后进行删除 key </section></li> </ul> <blockquote data-tool="mdnice编辑器" style="margin-top: 20px;margin-bottom: 20px;padding: 10px 10px 10px 20px;border-top: 3px none rgba(0, 0, 0, 0.4);border-bottom: 3px none rgba(0, 0, 0, 0.4);border-right: 3px none rgba(0, 0, 0, 0.4);border-left-color: rgb(255, 177, 27);border-radius: 0px;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;box-shadow: rgba(0, 0, 0, 0) 0px 0px 0px 0px;overflow: auto;"> 核心步骤：加锁、解锁和续时 </blockquote> <h4 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;">加锁</h4> 使用了 <code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>RedisTemplate</code> 的 <code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>opsForValue.setIfAbsent</code> 方法，判断是否有 key，设定一个随机数 <code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>UUID.random().toString</code>，生成一个随机数作为 value。 从 redis 中获取锁之后，对 key 设定 <code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>expire</code> 失效时间，到期后自动释放锁。 按照这种设计，只有第一个成功设定 Key 的请求，才能进行后续的数据操作，后续其它请求由于无法获得锁资源，将会失败结束。 <h4 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;">超时问题</h4> 担心<code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;> pjp.proceed()</code> 切点执行的方法太耗时，导致 Redis 中的 key 由于超时提前释放了。 例如，线程 A 先获取锁，<code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>proceed</code> 方法耗时，超过了锁超时时间，到期释放了锁，这时另一个线程 B 成功获取 Redis 锁，两个线程同时对同一批数据进行操作，导致数据不准确。 <h4 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;">解决方案：增加一个「续时」</h4> 任务不完成，锁不释放： 维护了一个定时线程池 <code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>ScheduledExecutorService</code>，每隔 2s 去扫描加入队列中的 Task，判断是否失效时间是否快到了，公式为：<code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>【失效时间】<= 【当前时间】+【失效间隔（三分之一超时）】</code> <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="php"><code>/**</code><code> * 线程池，每个 JVM 使用一个线程去维护 keyAliveTime，定时执行 runnable</code><code> */</code><code>private static final ScheduledExecutorService SCHEDULER = </code><code>new ScheduledThreadPoolExecutor(1, </code><code>new BasicThreadFactory.Builder().namingPattern("redisLock-schedule-pool").daemon(true).build());</code><code>static {</code><code> SCHEDULER.scheduleAtFixedRate(() -> {</code><code> // do something to extend time</code><code> }, 0, 2, TimeUnit.SECONDS);</code><code>}</code></pre> </section> <h3 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;border-style: none;border-width: 1px;border-color: rgb(0, 0, 0);border-radius: 0px;box-shadow: none;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow: unset;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-left: 20px;border-style: none none none solid;border-width: 1px 1px 1px 3px;border-color: rgb(0, 0, 0) rgb(0, 0, 0) rgb(0, 0, 0) rgb(255, 177, 27);border-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;overflow: unset;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">3. 设计方案</h3> 经过上面的分析，设计出了这个方案： <figure data-tool="mdnice编辑器" style="margin-top: 10px;margin-bottom: 10px;display: flex;flex-direction: column;justify-content: center;align-items: center;"> <img class="rich_pages wxw-img" data-imgfileid="100077200" data-ratio="0.6499508357915438" src="/upload/7e7fc9590a42376d79003986ba9a9ceb.png" data-type="png" data-w="1017" style="display: block;margin-right: auto;margin-left: auto;border-style: none;border-width: 3px;border-color: rgba(0, 0, 0, 0.4);border-radius: 4px;object-fit: fill;box-shadow: rgba(0, 0, 0, 0) 0px 0px 0px 0px;"> </figure> 前面已经说了整体流程，这里强调一下几个核心步骤： <ol data-tool="mdnice编辑器" style="margin-top: 8px;margin-bottom: 8px;padding-left: 25px;" class="list-paddingleft-1"> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(1, 1, 1);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 拦截注解 @RedisLock，获取必要的参数 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(1, 1, 1);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 加锁操作 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(1, 1, 1);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 续时操作 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(1, 1, 1);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 结束业务，释放锁 </section></li> </ol> <h3 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;border-style: none;border-width: 1px;border-color: rgb(0, 0, 0);border-radius: 0px;box-shadow: none;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow: unset;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-left: 20px;border-style: none none none solid;border-width: 1px 1px 1px 3px;border-color: rgb(0, 0, 0) rgb(0, 0, 0) rgb(0, 0, 0) rgb(255, 177, 27);border-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;overflow: unset;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">4. 实操</h3> 之前也有整理过 AOP 使用方法，可以参考一下 <blockquote data-tool="mdnice编辑器" style="margin-top: 20px;margin-bottom: 20px;padding: 10px 10px 10px 20px;border-top: 3px none rgba(0, 0, 0, 0.4);border-bottom: 3px none rgba(0, 0, 0, 0.4);border-right: 3px none rgba(0, 0, 0, 0.4);border-left-color: rgb(255, 177, 27);border-radius: 0px;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;box-shadow: rgba(0, 0, 0, 0) 0px 0px 0px 0px;overflow: auto;"> 相关属性类配置 </blockquote> <h5 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;">业务属性枚举设定 <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="typescript"><code>public enum RedisLockTypeEnum {</code><code> /**</code><code> * 自定义 key 前缀</code><code> */</code><code> ONE("Business1", "Test1"),</code><code> </code><code> TWO("Business2", "Test2");</code><code> private String code;</code><code> private String desc;</code><code> RedisLockTypeEnum(String code, String desc) {</code><code> this.code = code;</code><code> this.desc = desc;</code><code> }</code><code> public String getCode() {</code><code> return code;</code><code> }</code><code> public String getDesc() {</code><code> return desc;</code><code> }</code><code> public String getUniqueKey(String key) {</code><code> return String.format("%s:%s", this.getCode(), key);</code><code> }</code><code>}</code></pre> </section></h5> <h5 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;">任务队列保存参数 <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="cs"><code>public class RedisLockDefinitionHolder {</code><code> /**</code><code> * 业务唯一 key</code><code> */</code><code> private String businessKey;</code><code> /**</code><code> * 加锁时间 (秒 s)</code><code> */</code><code> private Long lockTime;</code><code> /**</code><code> * 上次更新时间（ms）</code><code> */</code><code> private Long lastModifyTime;</code><code> /**</code><code> * 保存当前线程</code><code> */</code><code> private Thread currentTread;</code><code> /**</code><code> * 总共尝试次数</code><code> */</code><code> private int tryCount;</code><code> /**</code><code> * 当前尝试次数</code><code> */</code><code> private int currentCount;</code><code> /**</code><code> * 更新的时间周期（毫秒）,公式 = 加锁时间（转成毫秒） / 3</code><code> */</code><code> private Long modifyPeriod;</code><code> public RedisLockDefinitionHolder(String businessKey, Long lockTime, Long lastModifyTime, Thread currentTread, int tryCount) {</code><code> this.businessKey = businessKey;</code><code> this.lockTime = lockTime;</code><code> this.lastModifyTime = lastModifyTime;</code><code> this.currentTread = currentTread;</code><code> this.tryCount = tryCount;</code><code> this.modifyPeriod = lockTime * 1000 / 3;</code><code> }</code><code>}</code></pre> </section></h5> <h5 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;">设定被拦截的注解名字 <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="cs"><code>@Retention(RetentionPolicy.RUNTIME)</code><code>@Target({ElementType.METHOD, ElementType.TYPE})</code><code>public @interface RedisLockAnnotation {</code><code> /**</code><code> * 特定参数识别，默认取第 0 个下标</code><code> */</code><code> int lockFiled() default 0;</code><code> /**</code><code> * 超时重试次数</code><code> */</code><code> int tryCount() default 3;</code><code> /**</code><code> * 自定义加锁类型</code><code> */</code><code> RedisLockTypeEnum typeEnum();</code><code> /**</code><code> * 释放时间，秒 s 单位</code><code> */</code><code> long lockTime() default 30;</code><code>}</code></pre> </section></h5> <h5 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;">核心切面拦截的操作</h5> <code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>RedisLockAspect.java</code> 该类分成三部分来描述具体作用 <strong style="color: rgb(0, 0, 0);background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;border-style: none;border-width: 3px;border-color: rgba(0, 0, 0, 0.4);border-radius: 0px;">Pointcut 设定 <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="css"><code>/**</code><code> * @annotation 中的路径表示拦截特定注解</code><code> */</code><code>@Pointcut("@annotation(cn.sevenyuan.demo.aop.lock.RedisLockAnnotation)")</code><code>public void redisLockPC() {</code><code>}</code></pre> </section> <strong style="color: rgb(0, 0, 0);background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;border-style: none;border-width: 3px;border-color: rgba(0, 0, 0, 0.4);border-radius: 0px;">Around 前后进行加锁和释放锁 前面步骤定义了我们想要拦截的切点，下一步就是在切点前后做一些自定义操作： <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="typescript"><code>@Around(value = "redisLockPC()")</code><code>public Object around(ProceedingJoinPoint pjp) throws Throwable {</code><code> // 解析参数</code><code> Method method = resolveMethod(pjp);</code><code> RedisLockAnnotation annotation = method.getAnnotation(RedisLockAnnotation.class);</code><code> RedisLockTypeEnum typeEnum = annotation.typeEnum();</code><code> Object[] params = pjp.getArgs();</code><code> String ukString = params[annotation.lockFiled()].toString();</code><code> // 省略很多参数校验和判空</code><code> String businessKey = typeEnum.getUniqueKey(ukString);</code><code> String uniqueValue = UUID.randomUUID().toString();</code><code> // 加锁</code><code> Object result = null;</code><code> try {</code><code> boolean isSuccess = redisTemplate.opsForValue().setIfAbsent(businessKey, uniqueValue);</code><code> if (!isSuccess) {</code><code> throw new Exception("You can't do it，because another has get the lock =-=");</code><code> }</code><code> redisTemplate.expire(businessKey, annotation.lockTime(), TimeUnit.SECONDS);</code><code> Thread currentThread = Thread.currentThread();</code><code> // 将本次 Task 信息加入「延时」队列中</code><code> holderList.add(new RedisLockDefinitionHolder(businessKey, annotation.lockTime(), System.currentTimeMillis(),</code><code> currentThread, annotation.tryCount()));</code><code> // 执行业务操作</code><code> result = pjp.proceed();</code><code> // 线程被中断，抛出异常，中断此次请求</code><code> if (currentThread.isInterrupted()) {</code><code> throw new InterruptedException("You had been interrupted =-=");</code><code> }</code><code> } catch (InterruptedException e ) {</code><code> log.error("Interrupt exception, rollback transaction", e);</code><code> throw new Exception("Interrupt exception, please send request again");</code><code> } catch (Exception e) {</code><code> log.error("has some error, please check again", e);</code><code> } finally {</code><code> // 请求结束后，强制删掉 key，释放锁</code><code> redisTemplate.delete(businessKey);</code><code> log.info("release the lock, businessKey is [" + businessKey + "]");</code><code> }</code><code> return result;</code><code>}</code></pre> </section> 上述流程简单总结一下： <ul data-tool="mdnice编辑器" style="margin-top: 8px;margin-bottom: 8px;padding-left: 25px;" class="list-paddingleft-1"> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 解析注解参数，获取注解值和方法上的参数值 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> redis 加锁并且设置超时时间 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 将本次 Task 信息加入「延时」队列中，进行续时，方式提前释放锁 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 加了一个线程中断标志 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 结束请求，finally 中释放锁 </section></li> </ul> <strong style="color: rgb(0, 0, 0);background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;border-style: none;border-width: 3px;border-color: rgba(0, 0, 0, 0.4);border-radius: 0px;">续时操作 这里用了 <code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>ScheduledExecutorService</code>，维护了一个线程，不断对任务队列中的任务进行判断和延长超时时间： <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="cs"><code>// 扫描的任务队列</code><code>private static ConcurrentLinkedQueue <redislockdefinitionholder> holderList = new ConcurrentLinkedQueue(); </redislockdefinitionholder></code><code>/**</code><code> * 线程池，维护keyAliveTime</code><code> */</code><code>private static final ScheduledExecutorService SCHEDULER = new ScheduledThreadPoolExecutor(1,</code><code> new BasicThreadFactory.Builder().namingPattern("redisLock-schedule-pool").daemon(true).build());</code><code>{</code><code> // 两秒执行一次「续时」操作</code><code> SCHEDULER.scheduleAtFixedRate(() -> {</code><code> // 这里记得加 try-catch，否者报错后定时任务将不会再执行=-=</code><code> Iterator <redislockdefinitionholder> iterator = holderList.iterator(); </redislockdefinitionholder></code><code> while (iterator.hasNext()) {</code><code> RedisLockDefinitionHolder holder = iterator.next();</code><code> // 判空</code><code> if (holder == null) {</code><code> iterator.remove();</code><code> continue;</code><code> }</code><code> // 判断 key 是否还有效，无效的话进行移除</code><code> if (redisTemplate.opsForValue().get(holder.getBusinessKey()) == null) {</code><code> iterator.remove();</code><code> continue;</code><code> }</code><code> // 超时重试次数，超过时给线程设定中断</code><code> if (holder.getCurrentCount() > holder.getTryCount()) {</code><code> holder.getCurrentTread().interrupt();</code><code> iterator.remove();</code><code> continue;</code><code> }</code><code> // 判断是否进入最后三分之一时间</code><code> long curTime = System.currentTimeMillis();</code><code> boolean shouldExtend = (holder.getLastModifyTime() + holder.getModifyPeriod()) <= curTime;</code><code> if (shouldExtend) {</code><code> holder.setLastModifyTime(curTime);</code><code> redisTemplate.expire(holder.getBusinessKey(), holder.getLockTime(), TimeUnit.SECONDS);</code><code> log.info("businessKey : [" + holder.getBusinessKey() + "], try count : " + holder.getCurrentCount());</code><code> holder.setCurrentCount(holder.getCurrentCount() + 1);</code><code> }</code><code> }</code><code> }, 0, 2, TimeUnit.SECONDS);</code><code>}</code></pre> </section> 这段代码，用来实现设计图中虚线框的思想，避免一个请求十分耗时，导致提前释放了锁。 这里加了「线程中断」<code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>Thread#interrupt</code>，希望超过重试次数后，能让线程中断（未经严谨测试，仅供参考哈哈哈哈） 不过建议如果遇到这么耗时的请求，还是能够从根源上查找，分析耗时路径，进行业务优化或其它处理，避免这些耗时操作。 所以记得多打点 Log，分析问题时可以更快一点。记录项目日志，一个注解搞定 <h3 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;border-style: none;border-width: 1px;border-color: rgb(0, 0, 0);border-radius: 0px;box-shadow: none;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow: unset;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-left: 20px;border-style: none none none solid;border-width: 1px 1px 1px 3px;border-color: rgb(0, 0, 0) rgb(0, 0, 0) rgb(0, 0, 0) rgb(255, 177, 27);border-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;overflow: unset;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">5. 开始测试</h3> 在一个入口方法中，使用该注解，然后在业务中模拟耗时请求，使用了 <code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>Thread#sleep</code> <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="kotlin"><code>@GetMapping("/testRedisLock")</code><code>@RedisLockAnnotation(typeEnum = RedisLockTypeEnum.ONE, lockTime = 3)</code><code>public Book testRedisLock(@RequestParam("userId") Long userId) {</code><code> try {</code><code> log.info("睡眠执行前");</code><code> Thread.sleep(10000);</code><code> log.info("睡眠执行后");</code><code> } catch (Exception e) {</code><code> // log error</code><code> log.info("has some error", e);</code><code> }</code><code> return null;</code><code>}</code></pre> </section> 使用时，在方法上添加该注解，然后设定相应参数即可，根据 <code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>typeEnum</code> 可以区分多种业务，限制该业务被同时操作。 测试结果： <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="css"><code>2020-04-04 14:55:50.864 INFO 9326 --- [nio-8081-exec-1] c.s.demo.controller.BookController : 睡眠执行前</code><code>2020-04-04 14:55:52.855 INFO 9326 --- [k-schedule-pool] c.s.demo.aop.lock.RedisLockAspect : businessKey : [Business1:1024], try count : 0</code><code>2020-04-04 14:55:54.851 INFO 9326 --- [k-schedule-pool] c.s.demo.aop.lock.RedisLockAspect : businessKey : [Business1:1024], try count : 1</code><code>2020-04-04 14:55:56.851 INFO 9326 --- [k-schedule-pool] c.s.demo.aop.lock.RedisLockAspect : businessKey : [Business1:1024], try count : 2</code><code>2020-04-04 14:55:58.852 INFO 9326 --- [k-schedule-pool] c.s.demo.aop.lock.RedisLockAspect : businessKey : [Business1:1024], try count : 3</code><code>2020-04-04 14:56:00.857 INFO 9326 --- [nio-8081-exec-1] c.s.demo.controller.BookController : has some error</code><code>java.lang.InterruptedException: sleep interrupted</code><code> at java.lang.Thread.sleep(Native Method) [na:1.8.0_221]</code></pre> </section> 我这里测试的是重试次数过多，失败的场景，如果减少睡眠时间，就能让业务正常执行。 如果同时请求，你将会发现以下错误信息： <figure data-tool="mdnice编辑器" style="margin-top: 10px;margin-bottom: 10px;display: flex;flex-direction: column;justify-content: center;align-items: center;"> <img class="rich_pages wxw-img" data-imgfileid="100077199" data-ratio="0.06111111111111111" src="/upload/299b8c326135208734e3668eea816e53.png" data-type="png" data-w="1080" style="display: block;margin-right: auto;margin-left: auto;border-style: none;border-width: 3px;border-color: rgba(0, 0, 0, 0.4);border-radius: 4px;object-fit: fill;box-shadow: rgba(0, 0, 0, 0) 0px 0px 0px 0px;"> </figure> 表示我们的锁🔐的确生效了，避免了重复请求。 <h3 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;border-style: none;border-width: 1px;border-color: rgb(0, 0, 0);border-radius: 0px;box-shadow: none;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow: unset;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-left: 20px;border-style: none none none solid;border-width: 1px 1px 1px 3px;border-color: rgb(0, 0, 0) rgb(0, 0, 0) rgb(0, 0, 0) rgb(255, 177, 27);border-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position: 0% 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;overflow: unset;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">6. 总结</h3> 对于耗时业务和核心数据，不能让重复的请求同时操作数据，避免数据的不正确，所以要使用分布式锁来对它们进行保护。 再来梳理一下设计流程： <ul data-tool="mdnice编辑器" style="margin-top: 8px;margin-bottom: 8px;padding-left: 25px;" class="list-paddingleft-1"> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 新建注解 <code style="background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>@interface</code>，在注解里设定入参标志 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 增加 AOP 切点，扫描特定注解 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 建立 <code style="background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>@Aspect</code> 切面任务，注册 bean 和拦截特定方法 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 特定方法参数 <code style="background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>ProceedingJoinPoint</code>，对方法 <code style="background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>pjp.proceed()</code> 前后进行拦截 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(58, 58, 58);font-size: 15px;line-height: 1.8em;letter-spacing: 0em;"> 切点前进行加锁，任务执行后进行删除 key </section></li> </ul> 本次学习是通过 Review 小伙伴的代码设计，从中了解分布式锁的具体实现，仿照他的设计，重新写了一份简化版的业务处理。对于之前没考虑到的「续时」操作，这里使用了守护线程来定时判断和延长超时时间，避免了锁提前释放。 于是乎，同时回顾了三个知识点： 1、AOP 的实现和常用方法 2、定时线程池 <code style="color: rgb(155, 110, 35);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background: none 0% 0% / auto no-repeat scroll padding-box border-box rgb(255, 245, 227);width: auto;height: auto;margin-left: 2px;margin-right: 2px;padding: 2px 4px;border-style: none;border-width: 3px;border-color: rgb(0, 0, 0) rgba(0, 0, 0, 0.4) rgba(0, 0, 0, 0.4);border-radius: 4px;font-family: " operator mono, consolas, monaco, menlo, monospace;word-break: break-all;>ScheduledExecutorService</code> 的使用和参数含义 3、线程的含义以及用法（这个挺有意思的，可以深入再学习一下） </section>

根据官方案例使用milvus向量数据库打造问答RAG系统

作者：微信小助手

<section style="max-width: 100%;box-sizing: border-box;color: rgb(62, 62, 62);font-size: 16px;white-space: normal;background-color: rgb(255, 255, 255);overflow-wrap: break-word !important;margin-bottom: 0px;"> <section powered-by="xiumi.us" style="max-width: 100%;box-sizing: border-box;word-wrap: break-word !important;"> <section style="max-width: 100%;box-sizing: border-box;word-wrap: break-word !important;"> <section style="padding-right: 10px;padding-left: 10px;max-width: 100%;box-sizing: border-box;line-height: 1.6;word-wrap: break-word !important;"> <section style="max-width: 100%;box-sizing: border-box;word-wrap: break-word !important;"> <section style="max-width: 100%;box-sizing: border-box;word-wrap: break-word !important;"> <section style="padding-right: 30px;padding-left: 30px;max-width: 100%;box-sizing: border-box;line-height: 1.6;word-wrap: break-word !important;"> <section class="mp_profile_iframe_wrp"> <mp-common-profile class="js_uneditable custom_select_card mp_profile_iframe" data-pluginname="mpprofile" data-id="Mzg2NzAzMDMwOA==" data-headimg="http://mmbiz.qpic.cn/sz_mmbiz_png/0arf3teEpjCjeKrgtiajadiadeQyY7ia9LBlhQNuGwdHvj5kk4Jm4Cos7ImoCE8lNh4pf2WGuUknxohQicBy7WlmNw/0?wx_fmt=png" data-nickname="烟火的成长" data-alias="" data-signature="记录个人成长，理财，感悟和思考" data-from="0" data-is_biz_ban="0"></mp-common-profile> </section> “ 向量数据库是RAG技术的重要底座之一 ” </section> </section> </section> <section style="max-width: 100%;box-sizing: border-box;word-wrap: break-word !important;"> <section style="max-width: 100%;box-sizing: border-box;word-wrap: break-word !important;"> <section style="padding-right: 22px;padding-left: 22px;max-width: 100%;box-sizing: border-box;line-height: 1.6;word-wrap: break-word !important;"> </section> </section> </section> 关于RAG和向量数据库的基础知识这里就不再做介绍了，不懂的可以翻看之前的文章。 今天的主要目的是使用milvus向量数据库来实现RAG检索增强，后面会附上代码。 </section> </section> </section> </section> <p style="max-width: 100%;min-height: 1em;color: rgb(62, 62, 62);font-size: 16px;white-space: normal;background-color: rgb(255, 255, 255);box-sizing: border-box !important;overflow-wrap: break-word !important;margin-bottom: 0px;"> <p style="max-width: 100%;min-height: 1em;color: rgb(62, 62, 62);font-size: 16px;white-space: normal;background-color: rgb(255, 255, 255);box-sizing: border-box !important;overflow-wrap: break-word !important;margin-bottom: 0px;"> <p style="max-width: 100%;min-height: 1em;color: rgb(62, 62, 62);white-space: normal;background-color: rgb(255, 255, 255);text-align: center;margin-bottom: 0px;box-sizing: border-box !important;overflow-wrap: break-word !important;">使用milvus实现RAG‍‍‍‍ <p style="max-width: 100%;min-height: 1em;color: rgb(62, 62, 62);font-size: 16px;white-space: normal;background-color: rgb(255, 255, 255);box-sizing: border-box !important;overflow-wrap: break-word !important;margin-bottom: 0px;"> <p style="max-width: 100%;min-height: 1em;color: rgb(62, 62, 62);font-size: 16px;white-space: normal;background-color: rgb(255, 255, 255);box-sizing: border-box !important;overflow-wrap: break-word !important;margin-bottom: 0px;"> <section style="max-width: 100%;box-sizing: border-box;text-wrap-mode: wrap;background-color: rgb(255, 255, 255);margin-bottom: 0px;overflow-wrap: break-word !important;"> <section powered-by="xiumi.us" style="max-width: 100%;box-sizing: border-box;overflow-wrap: break-word !important;"> <section style="max-width: 100%;box-sizing: border-box;overflow-wrap: break-word !important;"> <section style="padding-right: 10px;padding-left: 10px;max-width: 100%;box-sizing: border-box;line-height: 1.6;overflow-wrap: break-word !important;"> RAG的核心在于检索，而与传统字符匹配和分词检索方式不同的是RAG主要是基于语义检索的方式，也就是向量检索。而一个好的向量数据库就成为RAG技术环节中必不可少的一环。‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ <blockquote class="js_blockquote_wrap" data-type="1" data-url="https://mp.weixin.qq.com/s/07N-0FXwFFxoZI-WbJHs8g" data-author-name="DFires" data-content-utf8-length="91" data-source-title="RAG与本地知识库，向量数据库，以及知识图谱的联系与区别" style="color: rgb(62, 62, 62);font-size: 16px;white-space-collapse: collapse;"> <section class="js_blockquote_digest"> <section> 备注：RAG并不是只支持向量检索，也可以使用传统的检索方式，主要根据不同的应用场景选择最合适的方式；RAG的核心是准确，高效的检索到有效数据，也就是说RAG重视的是结果，而不是过程。 </section> </section> <section class="blockquote_info js_blockquote_source" data-json="%7B%22type%22%3A%22inner%22%2C%22source%22%3A%22url%22%2C%22digest%22%3A%22%22%2C%22digestLen%22%3A91%2C%22text%22%3A%22%E5%A4%87%E6%B3%A8%EF%BC%9ARAG%E5%B9%B6%E4%B8%8D%E6%98%AF%E5%8F%AA%E6%94%AF%E6%8C%81%E5%90%91%E9%87%8F%E6%A3%80%E7%B4%A2%EF%BC%8C%E4%B9%9F%E5%8F%AF%E4%BB%A5%E4%BD%BF%E7%94%A8%E4%BC%A0%E7%BB%9F%E7%9A%84%E6%A3%80%E7%B4%A2%E6%96%B9%E5%BC%8F%EF%BC%8C%E4%B8%BB%E8%A6%81%E6%A0%B9%E6%8D%AE%E4%B8%8D%E5%90%8C%E7%9A%84%E5%BA%94%E7%94%A8%E5%9C%BA%E6%99%AF%E9%80%89%E6%8B%A9%E6%9C%80%E5%90%88%E9%80%82%E7%9A%84%E6%96%B9%E5%BC%8F%EF%BC%9BRAG%E7%9A%84%E6%A0%B8%E5%BF%83%E6%98%AF%E5%87%86%E7%A1%AE%EF%BC%8C%E9%AB%98%E6%95%88%E7%9A%84%E6%A3%80%E7%B4%A2%E5%88%B0%E6%9C%89%E6%95%88%E6%95%B0%E6%8D%AE%EF%BC%8C%E4%B9%9F%E5%B0%B1%E6%98%AF%E8%AF%B4RAG%E9%87%8D%E8%A7%86%E7%9A%84%E6%98%AF%E7%BB%93%E6%9E%9C%EF%BC%8C%E8%80%8C%E4%B8%8D%E6%98%AF%E8%BF%87%E7%A8%8B%E3%80%82%22%2C%22article%22%3A%7B%22title%22%3A%22RAG%E4%B8%8E%E6%9C%AC%E5%9C%B0%E7%9F%A5%E8%AF%86%E5%BA%93%EF%BC%8C%E5%90%91%E9%87%8F%E6%95%B0%E6%8D%AE%E5%BA%93%EF%BC%8C%E4%BB%A5%E5%8F%8A%E7%9F%A5%E8%AF%86%E5%9B%BE%E8%B0%B1%E7%9A%84%E8%81%94%E7%B3%BB%E4%B8%8E%E5%8C%BA%E5%88%AB%22%2C%22url%22%3A%22https%3A%2F%2Fmp.weixin.qq.com%2Fs%2F07N-0FXwFFxoZI-WbJHs8g%22%2C%22nickname%22%3A%22AI%E6%8E%A2%E7%B4%A2%E6%97%B6%E4%BB%A3%22%2C%22authorName%22%3A%22DFires%22%7D%2C%22hasReportOverSize%22%3Afalse%2C%22editorReportData%22%3A%5B%7B%22id%22%3A%22122333%22%2C%22key%22%3A%2275%22%2C%22len%22%3A1%7D%2C%7B%22id%22%3A%22122333%22%2C%22key%22%3A%2277%22%2C%22len%22%3A1%7D%2C%7B%22id%22%3A%22122333%22%2C%22key%22%3A%2278%22%2C%22len%22%3A1%7D%5D%7D"> DFires，公众号：AI探索时代<a href="https://mp.weixin.qq.com/s/07N-0FXwFFxoZI-WbJHs8g" class="blockquote_article">RAG与本地知识库，向量数据库，以及知识图谱的联系与区别</a> </section> </blockquote> milvus是我国企业自主开发的一款向量数据库，根据其官方介绍，milvus既可以方便本地开发测试，也可以大规模集群部署支持上百亿的向量检索需求。‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ 而且，milvus同时还支持多种检索方式和算法：‍‍‍‍‍ <img class="rich_pages wxw-img" data-galleryid="" data-imgfileid="100002386" data-ratio="0.6675925925925926" data-s="300,640" src="/upload/f07c57712269fb879fc219109b426ea9.png" data-type="png" data-w="1080" style=""> 并且集成多种语言的SDK：‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ <img class="rich_pages wxw-img" data-galleryid="" data-imgfileid="100002387" data-ratio="0.7230046948356808" data-s="300,640" src="/upload/b496c03161490be04ba5f8a04ee02255.png" data-type="png" data-w="852" style=""> 当然，今天的主要目的不是为了给milvus产品打广告，而是使用milvus实现RAG——检索增强问答系统。‍‍‍‍‍‍‍‍‍‍‍‍‍‍ <blockquote class="js_blockquote_wrap" data-type="2" data-url="" data-author-name="" data-content-utf8-length="25" data-source-title="milvus官方文档" style="color: rgb(62, 62, 62);font-size: 16px;white-space-collapse: collapse;"> <section class="js_blockquote_digest"> https://milvus.io/docs/zh </section> <section class="blockquote_info js_blockquote_source" data-json="%7B%22type%22%3A%22out%22%2C%22source%22%3A%22url%22%2C%22digest%22%3A%22%3Cp%3Ehttps%3A%2F%2Fmilvus.io%2Fdocs%2Fzh%3C%2Fp%3E%22%2C%22digestLen%22%3A25%2C%22text%22%3A%22%22%2C%22article%22%3A%7B%7D%2C%22hasReportOverSize%22%3Afalse%2C%22editorReportData%22%3A%5B%7B%22id%22%3A%22122333%22%2C%22key%22%3A%2276%22%2C%22len%22%3A1%7D%5D%2C%22from%22%3A%22milvus%E5%AE%98%E6%96%B9%E6%96%87%E6%A1%A3%22%7D"> milvus官方文档 </section> </blockquote> <mpcpc js_editor_cpcad="" class="js_cpc_area res_iframe cpc_iframe" src="/cgi-bin/readtemplate?t=tmpl/cpc_tmpl#1734253143487" data-category_id_list="1|2|5|6|7|8|16|17|21|24|28|29|31|35|36|37|39|41|42|43|46|47|48|50|51|55|56|57|58|59|60|61|62|63|64|65|66|67|68" data-id="1734253143487"></mpcpc> 安装milvus‍‍‍‍‍‍‍ milvus有多种版本，每种版本支持的场景不太一样，但安装方式都非常简单。‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ 轻量级可以直接通过pip进行安装，并直接嵌入到python代码中：‍‍‍‍‍‍‍‍‍ <section class="code-snippet__fix code-snippet__js"> <pre class="code-snippet__js" data-lang="nginx"><code># 本地python sdk 使用</code><code>pip install mivlus</code></pre> </section> 而单机版和集群版都是通过docker 进行安装，官方提供了详细的安装命令：‍ <section class="code-snippet__fix code-snippet__js"> <pre class="code-snippet__js" data-lang="nginx"><code># 单机安装 linux系统需要梯子</code><code>curl -sfL https://raw.githubusercontent.com/milvus-io/milvus/master/scripts/standalone_embed.sh -o standalone_embed.sh</code><code> </code><code>bash standalone_embed.sh start</code><code> </code></pre> </section> <table style="color: rgb(62, 62, 62);font-size: 16px;white-space-collapse: collapse;"> <tbody> <tr> <td width="156.66666666666666" valign="top" style="word-break: break-all;">版本‍‍‍‍</td> <td width="118.66666666666666" valign="top" style="word-break: break-all;">说明</td> <td width="138" valign="top" style="word-break: break-all;">使用场景‍‍</td> <td width="138" valign="top" style="word-break: break-all;">数据量‍‍‍‍</td> </tr> <tr> <td width="157" valign="top" style="word-break: break-all;">milvus Lite </td> <td width="118.66666666666666" valign="top" style="word-break: break-all;">轻量级版本</td> <td width="138" valign="top" style="word-break: break-all;">常用于本地开发使用‍‍‍</td> <td width="138" valign="top" style="word-break: break-all;">百万到千万级向量数据‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍</td> </tr> <tr> <td width="157" valign="top" style="word-break: break-all;">milvus Standalone</td> <td width="118.66666666666666" valign="top" style="word-break: break-all;">单机版‍‍‍‍‍</td> <td width="138" valign="top" style="word-break: break-all;">常用于小规模用户使用‍‍‍‍‍‍</td> <td width="138" valign="top" style="word-break: break-all;">上亿级向量数据‍</td> </tr> <tr> <td width="157" valign="top" style="word-break: break-all;">milvus Distributed</td> <td width="118.66666666666666" valign="top" style="word-break: break-all;">集群版‍‍‍‍‍‍‍</td> <td width="138" valign="top" style="word-break: break-all;">常用于大规模业务场景‍‍</td> <td width="138" valign="top" style="word-break: break-all;">百亿级向量数据</td> </tr> </tbody> </table> 为了方便管理，milvus提供了一个可视化的客户端工具——attu，只需要一个命令就可以安装：‍‍ <section class="code-snippet__fix code-snippet__js"> <pre class="code-snippet__js" data-lang="nginx"><code># attu 安装命令 这个{milvus server IP} 要换成你自己的服务器地址或本地地址 </code><code>docker run -p 8000:3000 -e MILVUS_URL={milvus server IP}:19530 zilliz/attu:v2.4</code><code> </code><code>项目地址： https://github.com/zilliztech/attu</code></pre> </section> 这里有一个坑， <span style="white-space:pre-wrap;caret-color: rgb(51, 51, 51);color: rgb(51, 51, 51);font-family: Consolas, " liberation mono, menlo, courier, monospace;font-size: 14px;letter-spacing: 0.578px;text-align: left;background-color: rgb(250, 250, 250);>zilliz/attu:v2.4 attu的镜像有些平台会拉不下来，大家可以换个思路使用自己的电脑或者能够拉下attu镜像的服务器，拉取之后把使用 save命令把镜像保存下来，然后再部署到你的电脑或服务器上。‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ 当然，attu客户端工具并不是必须的，只是方便管理milvus ，也可以不使用。‍‍‍‍‍‍‍‍ 如下是attu的管理页面：‍‍ <img class="rich_pages wxw-img" data-galleryid="" data-imgfileid="100002388" data-ratio="0.6361111111111111" data-s="300,640" src="/upload/c1bc05f20dcbd9e0cbfa1c588a03bfd4.png" data-type="png" data-w="1080" style=""> 用户本地或在服务上安装好milvus向量数据库之后，就可以直接使用了。‍‍‍‍ 在python 中连接milvus数据库的方式有两种，然后用户所有与milvus数据库的操作都可以基于milvus_client客户端对象实现。‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ <section class="code-snippet__fix code-snippet__js"> <pre class="code-snippet__js" data-lang="ini"><code># milvus 客户端有两种连接方式一种是本地开发测试使用一种是独立部署</code><code># 独立部署方式</code><code># milvus_client = MilvusClient(</code><code># uri="你的milvus ip:19530",</code><code># token="root:milvus" # 默认用户名和密码 </code><code># )</code><code> </code><code># 本地方式会在本地创建一个milvus 数据库</code><code>milvus_client = MilvusClient("milvus_demo.db")</code></pre> </section> 其次，milvus也像传统的关系型数据库一样，拥有数据库的概念；不同的数据可以放到不同的数据库中，默认数据库就是default，如果你没有声明或创建数据库，那么你的数据默认都在default数据库中。 但milvus的主要操作是通过Collections来实现的；Collections就类似于传统数据库中的表结构。‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ 如下图所示： <img class="rich_pages wxw-img" data-galleryid="" data-imgfileid="100002389" data-ratio="0.65" data-s="300,640" src="/upload/d8754a33bba7c95255eca7b2da82ab67.png" data-type="png" data-w="1080" style=""> 在学会milvus数据库的基本使用之后，就可以通过嵌入模型把数据导入到milvus数据库的collection中；然后通过调用大模型实现RAG问答。‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ <blockquote class="js_blockquote_wrap" data-type="2" data-url="" data-author-name="" data-content-utf8-length="65" data-source-title=""> <section class="js_blockquote_digest"> <section> 详细实现可以查看官方文档：‍‍ https://milvus.io/docs/zh/build-rag-with-milvus.md </section> </section> </blockquote> 完整代码如下所示，这里使用的是阿里云的通义千问模型，嵌入模型使用的也是阿里云的嵌入模型；当然milvus官方也提供了一些嵌入模型，用户也可以根据自己的喜好选择一些第三方的模型。‍‍‍‍‍‍‍‍‍‍‍‍‍‍ 需要安装的python 包，当然作者这里只是记录了一部分包，如果代码执行出错提示缺包，用户自行下载即可。‍‍‍‍‍‍‍‍‍‍‍‍ <section class="code-snippet__fix code-snippet__js"> <pre class="code-snippet__js" data-lang="sql"><code>!pip install jq</code><code>!pip install pymilvus[model]</code><code>!pip install pymilvus</code><code>!pip install tqdm</code><code>!pip install openai</code><code> </code><code># python 环境是3.9</code></pre> </section> ‍‍‍‍‍ 这里的代码是完整的可执行代码，只需要把文件路径换成你本地下载的文件即可；还有就是大模型客户端可以选择你自己的模型和key。‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍ 这里的测试文件使用的是milvus官方提供的问题文档，下载地址：‍‍‍‍‍‍ <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="javascript"><code>https://github.com/milvus-io/milvus-docs/releases/download/v2.4.6-preview/milvus_docs_2.4.x_en.zip</code></pre> </section> <section class="code-snippet__fix code-snippet__js"> <pre class="code-snippet__js" data-lang="python"><code>from glob import glob</code><code>from openai import OpenAI</code><code>from pymilvus import MilvusClient</code><code>from tqdm import tqdm</code><code>import json</code><code> </code><code>text_lines = []</code><code> </code><code># 路径 milvus_docs/en/faq/*.md</code><code>for file_path in glob("换成你的文件路径", recursive=True):</code><code> with open(file_path, "r") as file:</code><code> file_text = file.read()</code><code> </code><code> text_lines += file_text.split("# ")</code><code> </code><code>print("text_lines: ", text_lines)</code><code> </code><code># 这里使用的是openai的工具包可以连接openai, 通义千问, 等多种兼容openai格式的大模型服务商这里使用的是阿里的通义千问模型</code><code>openai_client = OpenAI(</code><code> api_key="换成你的key",</code><code> base_url="https://dashscope.aliyuncs.com/compatible-mode/v1"</code><code>)</code><code> </code><code># 嵌入模型</code><code>def emb_text(text):</code><code> return (</code><code> openai_client.embeddings.create(input=text, model="text-embedding-v3").data[0].embedding</code><code> )</code><code> </code><code> </code><code>test_embedding = emb_text("This is a test")</code><code> </code><code>embedding_dim = len(test_embedding)</code><code> </code><code>print(embedding_dim)</code><code>print(test_embedding[:10])</code><code> </code><code># milvus 客户端有两种连接方式一种是本地开发测试使用一种是独立部署</code><code># 独立部署方式</code><code># milvus_client = MilvusClient(</code><code># uri="你的milvus ip:19530",</code><code># token="root:milvus"</code><code># )</code><code> </code><code># 本地方式会在本地创建一个milvus 数据库</code><code>milvus_client = MilvusClient("milvus_demo.db")</code><code> </code><code>collection_name = "my_rag_collection"</code><code> </code><code>if milvus_client.has_collection(collection_name):</code><code> milvus_client.drop_collection(collection_name)</code><code> </code><code>milvus_client.create_collection(</code><code> collection_name=collection_name,</code><code> dimension=embedding_dim,</code><code> metric_type="IP",</code><code> consistency_level="Strong"</code><code>)</code><code> </code><code>data = []</code><code> </code><code>for i, line in enumerate(tqdm(text_lines, desc="Creating embeddings")):</code><code> data.append({"id": i, "vector": emb_text(line), "text": line})</code><code> </code><code>print("data: ", len(data))</code><code> </code><code>milvus_client.insert(collection_name=collection_name, data=data)</code><code> </code><code>question = "How is data stored in milvus?"</code><code> </code><code>search_res = milvus_client.search(</code><code> collection_name=collection_name,</code><code> data=[</code><code> emb_text(question)</code><code> ],</code><code> limit=3,</code><code> search_params={"metric_type": "IP", "params": {}},</code><code> output_fields=["text"]</code><code>)</code><code> </code><code>retrieved_lines_with_distances = [</code><code> (res["entity"]["text"], res["distance"]) for res in search_res[0]</code><code>]</code><code> </code><code>print("retrieved: ", retrieved_lines_with_distances)</code><code> </code><code>print(json.dumps(retrieved_lines_with_distances, indent=4))</code><code> </code><code>context = "\n".join(</code><code> [line_with_distance[0] for line_with_distance in retrieved_lines_with_distances]</code><code>)</code><code> </code><code>SYSTEM_PROMPT = """</code><code>Human: You are an AI assistant. You are able to find answers to the questions from the contextual passage snippets provided.</code><code>"""</code><code>USER_PROMPT = f"""</code><code>Use the following pieces of information enclosed in <context> tags to provide an answer to the question enclosed in <question> tags. </question> </context></code><code> <context></context></code><code>{context}</code><code></code><code> <question></question></code><code>{question}</code><code></code><code>"""</code><code> </code><code>response = openai_client.chat.completions.create(</code><code>    model="qwen-plus", # 可以换成你自己喜欢的模型</code><code> messages=[</code><code> {"role": "system", "content": SYSTEM_PROMPT},</code><code> {"role": "user", "content": USER_PROMPT},</code><code> ],</code><code>)</code><code>print(response.choices[0].message.content)</code><code> </code><code> </code></pre> </section> </section> </section> </section> </section> 当然，上面文章写的不明白的地方，用户可以自己看milvus的官方文档，操作起来真的特别简单，这个案例就是作者自己根据milvus的官方文档实现的。‍‍‍ <blockquote class="js_blockquote_wrap" data-type="2" data-url="" data-author-name="" data-content-utf8-length="58" data-source-title=""> <section class="js_blockquote_digest"> <section> 文档地址：https://milvus.io/docs/zh/build-rag-with-milvus.md‍‍‍ </section> </section> </blockquote> <section class="mp_profile_iframe_wrp"> <mp-common-profile class="js_uneditable custom_select_card mp_profile_iframe" data-pluginname="mpprofile" data-id="Mzg2NzAzMDMwOA==" data-headimg="http://mmbiz.qpic.cn/sz_mmbiz_png/0arf3teEpjCjeKrgtiajadiadeQyY7ia9LBlhQNuGwdHvj5kk4Jm4Cos7ImoCE8lNh4pf2WGuUknxohQicBy7WlmNw/0?wx_fmt=png" data-nickname="烟火的成长" data-alias="" data-signature="记录个人成长，理财，感悟和思考" data-from="0" data-is_biz_ban="0"></mp-common-profile> </section> <mp-style-type data-value="3"></mp-style-type>

Billd-Live：竟然bilibili也开源了吗？完美的在线视频解决方案，需要的同学还不抓紧入手，知识点特别多~~~

作者：微信小助手

Springboot集成Easy Rules引擎，实现一个商品优惠券系统

作者：微信小助手

<section data-tool="mdnice编辑器" data-website="https://www.mdnice.com" style="margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 10px;padding-right: 10px;background-attachment: scroll;background-clip: border-box;background-color: rgba(0, 0, 0, 0);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;font-family: Optima, PingFangSC-light, serif;font-size: 16px;color: rgb(0, 0, 0);line-height: 1.5em;word-spacing: 0em;letter-spacing: 0em;word-break: break-word;overflow-wrap: break-word;text-align: left;"> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">Easy Rules是一个轻量级的Java规则引擎，它允许开发者将业务规则从代码中解耦出来，使规则的管理和执行更加灵活。 <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">现在让我们一起利用Spring Boot结合Easy Rules和MyBatis技术栈，可以实现一个高效且易于维护的优惠券系统例子。 <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">1. 添加依赖项</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">在 <code style="color: rgb(248, 57, 41);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background-attachment: scroll;background-clip: border-box;background-color: rgba(27, 31, 35, 0.05);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;margin-top: 0px;margin-bottom: 0px;margin-left: 2px;margin-right: 2px;padding-top: 2px;padding-bottom: 2px;padding-left: 4px;padding-right: 4px;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 3px;border-bottom-width: 3px;border-left-width: 3px;border-right-width: 3px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgba(0, 0, 0, 0.4);border-left-color: rgba(0, 0, 0, 0.4);border-right-color: rgba(0, 0, 0, 0.4);border-top-left-radius: 4px;border-top-right-radius: 4px;border-bottom-right-radius: 4px;border-bottom-left-radius: 4px;overflow-wrap: break-word;font-family: 'Operator Mono', Consolas, Monaco, Menlo, monospace;word-break: break-all;">pom.xml</code> 文件中确保包含以下依赖项： <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;"><dependencies>          <dependency>         <groupId>org.springframework.bootgroupId>         <artifactId>spring-boot-starter-webartifactId>     dependency>          <dependency>         <groupId>org.mybatis.spring.bootgroupId>         <artifactId>mybatis-spring-boot-starterartifactId>         <version>3.0.1version>     dependency>          <dependency>         <groupId>mysqlgroupId>         <artifactId>mysql-connector-javaartifactId>         <scope>runtimescope>     dependency>          <dependency>         <groupId>org.jeasygroupId>         <artifactId>easy-rules-coreartifactId>         <version>4.4.0version>     dependency>          <dependency>         <groupId>org.jeasygroupId>         <artifactId>easy-rules-support-springartifactId>         <version>4.4.0version>     dependency>          <dependency>         <groupId>org.projectlombokgroupId>         <artifactId>lombokartifactId>         <optional>trueoptional>     dependency>          <dependency>         <groupId>org.springframework.bootgroupId>         <artifactId>spring-boot-starter-testartifactId>         <scope>testscope>     dependency> dependencies> </code></pre> <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">2. 配置 MyBatis 和数据库连接</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">在 <code style="color: rgb(248, 57, 41);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background-attachment: scroll;background-clip: border-box;background-color: rgba(27, 31, 35, 0.05);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;margin-top: 0px;margin-bottom: 0px;margin-left: 2px;margin-right: 2px;padding-top: 2px;padding-bottom: 2px;padding-left: 4px;padding-right: 4px;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 3px;border-bottom-width: 3px;border-left-width: 3px;border-right-width: 3px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgba(0, 0, 0, 0.4);border-left-color: rgba(0, 0, 0, 0.4);border-right-color: rgba(0, 0, 0, 0.4);border-top-left-radius: 4px;border-top-right-radius: 4px;border-bottom-right-radius: 4px;border-bottom-left-radius: 4px;overflow-wrap: break-word;font-family: 'Operator Mono', Consolas, Monaco, Menlo, monospace;word-break: break-all;">application.properties</code> 文件中配置数据库连接信息和 MyBatis 设置： <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;"># 数据库配置 spring.datasource.url=jdbc:mysql://localhost:3306/coupon_system?useSSL=false&serverTimezone=UTC spring.datasource.username=root spring.datasource.password=root spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver # MyBatis 配置 mybatis.type-aliases-package=com.example.couponsystemdb.model mybatis.mapper-locations=classpath*:mapper/*.xml </code></pre> <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">3. 定义业务实体类</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">我们需要定义一些业务实体类来表示购物车、商品和优惠券信息。 <h2 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: block;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow-x: unset;overflow-y: unset;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;text-align: left;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-top: 0px;padding-bottom: 0px;padding-left: 10px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: solid;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 5px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(248, 57, 41);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">ShoppingCart.java</h2> <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">package com.example.couponsystemdb.model; import lombok.Data; import java.util.ArrayList; import java.util.List; @Data publicclass ShoppingCart {     privatedouble totalPrice = 0; // 购物车总价格     privatefinal List <item> items =  </item>new ArrayList<>(); // 商品列表     /**      * 向购物车添加商品      * @param item 商品对象      */     public void addItem(Item item) {         items.add(item);         totalPrice += item.getPrice();     }     /**      * 应用折扣      * @param discount 折扣比例（例如 0.10 表示 10% 折扣）      */     public void applyDiscount(double discount) {         totalPrice -= totalPrice * discount;     } } </code></pre> <h2 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: block;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow-x: unset;overflow-y: unset;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;text-align: left;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-top: 0px;padding-bottom: 0px;padding-left: 10px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: solid;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 5px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(248, 57, 41);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">Item.java</h2> <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">package com.example.couponsystemdb.model; import lombok.Data; @Data publicclass Item {     private String name; // 商品名称     private String category; // 商品类别     privatedouble price; // 商品价格     /**      * 构造函数      * @param name 商品名称      * @param category 商品类别      * @param price 商品价格      */     public Item(String name, String category, double price) {         this.name = name;         this.category = category;         this.price = price;     } } </code></pre> <h2 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: block;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow-x: unset;overflow-y: unset;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;text-align: left;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-top: 0px;padding-bottom: 0px;padding-left: 10px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: solid;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 5px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(248, 57, 41);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">CouponRule.java</h2> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">这个类用于从数据库加载规则信息。 <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">package com.example.couponsystemdb.model; import lombok.Data; @Data public class CouponRule {     private Long id; // 规则ID     private String ruleName; // 规则名称     private String description; // 规则描述     private String conditionExpression; // 条件表达式     private String actionExpression; // 动作表达式 } </code></pre> <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">4. 创建数据库表和初始化数据</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">创建一个名为 <code style="color: rgb(248, 57, 41);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background-attachment: scroll;background-clip: border-box;background-color: rgba(27, 31, 35, 0.05);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;margin-top: 0px;margin-bottom: 0px;margin-left: 2px;margin-right: 2px;padding-top: 2px;padding-bottom: 2px;padding-left: 4px;padding-right: 4px;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 3px;border-bottom-width: 3px;border-left-width: 3px;border-right-width: 3px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgba(0, 0, 0, 0.4);border-left-color: rgba(0, 0, 0, 0.4);border-right-color: rgba(0, 0, 0, 0.4);border-top-left-radius: 4px;border-top-right-radius: 4px;border-bottom-right-radius: 4px;border-bottom-left-radius: 4px;overflow-wrap: break-word;font-family: 'Operator Mono', Consolas, Monaco, Menlo, monospace;word-break: break-all;">coupon_system</code> 的数据库，并在其中创建 <code style="color: rgb(248, 57, 41);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background-attachment: scroll;background-clip: border-box;background-color: rgba(27, 31, 35, 0.05);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;margin-top: 0px;margin-bottom: 0px;margin-left: 2px;margin-right: 2px;padding-top: 2px;padding-bottom: 2px;padding-left: 4px;padding-right: 4px;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 3px;border-bottom-width: 3px;border-left-width: 3px;border-right-width: 3px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgba(0, 0, 0, 0.4);border-left-color: rgba(0, 0, 0, 0.4);border-right-color: rgba(0, 0, 0, 0.4);border-top-left-radius: 4px;border-top-right-radius: 4px;border-bottom-right-radius: 4px;border-bottom-left-radius: 4px;overflow-wrap: break-word;font-family: 'Operator Mono', Consolas, Monaco, Menlo, monospace;word-break: break-all;">coupon_rule</code> 表。然后插入一些初始规则数据。 <h2 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: block;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow-x: unset;overflow-y: unset;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;text-align: left;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-top: 0px;padding-bottom: 0px;padding-left: 10px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: solid;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 5px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(248, 57, 41);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">SQL 脚本</h2> <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">CREATE DATABASE coupon_system; USE coupon_system; CREATETABLE coupon_rule (     idBIGINT AUTO_INCREMENT PRIMARY KEY,     rule_name VARCHAR(255) NOTNULL,     description TEXT,     condition_expression TEXTNOTNULL,     action_expression TEXTNOTNULL ); INSERTINTO coupon_rule (rule_name, description, condition_expression, action_expression) VALUES ('Total Price Discount Rule', 'Offers a 10% discount if the total price exceeds 1000', 'cart.getTotalPrice() > 1000', 'cart.applyDiscount(0.10); System.out.println("Applied 10% discount for total price exceeding 1000");'), ('Category Discount Rule', 'Offers an additional 5% discount on Electronics category', 'cart.getItems().stream().anyMatch(item -> item.getCategory().equals("Electronics"))', 'cart.applyDiscount(0.05); System.out.println("Applied 5% discount for purchasing electronics");'); </code></pre> <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">5. 定义动态规则</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">我们将使用 Easy Rules 的 <code style="color: rgb(248, 57, 41);font-size: 14px;line-height: 1.8em;letter-spacing: 0em;background-attachment: scroll;background-clip: border-box;background-color: rgba(27, 31, 35, 0.05);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;margin-top: 0px;margin-bottom: 0px;margin-left: 2px;margin-right: 2px;padding-top: 2px;padding-bottom: 2px;padding-left: 4px;padding-right: 4px;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 3px;border-bottom-width: 3px;border-left-width: 3px;border-right-width: 3px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgba(0, 0, 0, 0.4);border-left-color: rgba(0, 0, 0, 0.4);border-right-color: rgba(0, 0, 0, 0.4);border-top-left-radius: 4px;border-top-right-radius: 4px;border-bottom-right-radius: 4px;border-bottom-left-radius: 4px;overflow-wrap: break-word;font-family: 'Operator Mono', Consolas, Monaco, Menlo, monospace;word-break: break-all;">DynamicRule</code> 类来从数据库加载规则并执行。 <h2 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: block;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow-x: unset;overflow-y: unset;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;text-align: left;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-top: 0px;padding-bottom: 0px;padding-left: 10px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: solid;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 5px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(248, 57, 41);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">DynamicCouponRule.java</h2> <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">package com.example.couponsystemdb.rule; import org.jeasy.rules.annotation.Action; import org.jeasy.rules.annotation.Condition; import org.jeasy.rules.annotation.Fact; import org.jeasy.rules.api.Facts; import org.jeasy.rules.core.DynamicRule; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; @Component publicclass DynamicCouponRule extends DynamicRule {     @Autowired     private CouponService couponService;     /**      * 评估条件      * @param facts 事实对象      * @return 是否满足条件      * @throws Exception 异常      */     @Override     @Condition     public boolean evaluate(Facts facts) throws Exception {         returnsuper.evaluate(facts);     }     /**      * 执行动作      * @param facts 事实对象      * @throws Exception 异常      */     @Override     @Action     public void execute(Facts facts) throws Exception {         super.execute(facts);     }     /**      * 从数据库设置规则      * @param ruleId 规则ID      */     public void setRuleFromDatabase(Long ruleId) {         CouponRule couponRule = couponService.getCouponRuleById(ruleId);         setName(couponRule.getRuleName());         setDescription(couponRule.getDescription());         setConditionExpression(couponRule.getConditionExpression());         setActionExpression(couponRule.getActionExpression());     } } </code></pre> <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">6. 配置规则引擎</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">我们需要配置规则引擎并将规则注册到 Spring 上下文中。 <h2 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: block;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow-x: unset;overflow-y: unset;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;text-align: left;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-top: 0px;padding-bottom: 0px;padding-left: 10px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: solid;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 5px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(248, 57, 41);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">EasyRulesConfig.java</h2> <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">package com.example.couponsystemdb.config; import org.jeasy.rules.api.RulesEngine; import org.jeasy.rules.core.DefaultRulesEngine; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration publicclass EasyRulesConfig {     /**      * 配置规则引擎      * @return 规则引擎实例      */     @Bean     public RulesEngine rulesEngine() {         returnnew DefaultRulesEngine();     } } </code></pre> <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">7. 创建 Service 层</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">创建一个服务层来处理与数据库的交互。 <h2 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: block;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow-x: unset;overflow-y: unset;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;text-align: left;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-top: 0px;padding-bottom: 0px;padding-left: 10px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: solid;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 5px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(248, 57, 41);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">CouponService.java</h2> <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">package com.example.couponsystemdb.service; import com.example.couponsystemdb.mapper.CouponRuleMapper; import com.example.couponsystemdb.model.CouponRule; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; @Service publicclass CouponService {     @Autowired     private CouponRuleMapper couponRuleMapper;     /**      * 根据规则ID获取规则      * @param id 规则ID      * @return 规则对象      */     public CouponRule getCouponRuleById(Long id) {         return couponRuleMapper.selectById(id);     } } </code></pre> <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">8. 创建 Mapper 接口</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">使用 MyBatis 映射器接口来操作数据库。 <h2 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: block;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow-x: unset;overflow-y: unset;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;text-align: left;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-top: 0px;padding-bottom: 0px;padding-left: 10px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: solid;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 5px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(248, 57, 41);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">CouponRuleMapper.java</h2> <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">package com.example.couponsystemdb.mapper; import com.example.couponsystemdb.model.CouponRule; import org.apache.ibatis.annotations.Mapper; import org.apache.ibatis.annotations.Select; @Mapper public interface CouponRuleMapper {     /**      * 根据规则ID查询规则      * @param id 规则ID      * @return 规则对象      */     @Select("SELECT * FROM coupon_rule WHERE id = #{id}")     CouponRule selectById(Long id); } </code></pre> <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">9. 编写主应用程序类</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">最后，在主应用程序类中使用规则引擎来处理购物车中的商品。 <h2 data-tool="mdnice编辑器" style="margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: block;flex-direction: unset;float: unset;height: auto;justify-content: unset;line-height: 1.5em;overflow-x: unset;overflow-y: unset;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;text-align: left;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 18px;color: rgb(34, 34, 34);line-height: 1.8em;letter-spacing: 0em;padding-top: 0px;padding-bottom: 0px;padding-left: 10px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: solid;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 5px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(248, 57, 41);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;box-shadow: none;display: block;font-weight: bold;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">CouponSystemApplication.java</h2> <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">package com.example.couponsystemdb; import com.example.couponsystemdb.model.ShoppingCart; import com.example.couponsystemdb.model.Item; import com.example.couponsystemdb.rule.DynamicCouponRule; import org.jeasy.rules.api.Facts; import org.jeasy.rules.api.Rules; import org.jeasy.rules.api.RulesEngine; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.CommandLineRunner; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication publicclass CouponSystemApplication implements CommandLineRunner {     @Autowired     private RulesEngine rulesEngine; // 规则引擎     @Autowired     private DynamicCouponRule dynamicCouponRule; // 动态规则     @Autowired     private CouponService couponService; // 优惠券服务     public static void main(String[] args) {         SpringApplication.run(CouponSystemApplication.class, args);     }     /**      * 应用启动时运行的方法      * @param args 命令行参数      * @throws Exception 异常      */     @Override     public void run(String... args) throws Exception {         ShoppingCart cart = new ShoppingCart(); // 创建购物车         cart.addItem(new Item("Laptop", "Electronics", 1200)); // 添加商品         cart.addItem(new Item("Book", "Books", 30)); // 添加商品         Facts facts = new Facts(); // 创建事实对象         facts.put("cart", cart); // 将购物车放入事实对象         Rules rules = new Rules(); // 创建规则集合         // 从数据库加载规则并注册到规则引擎         Long[] ruleIds = {1L, 2L}; // 数据库中的规则ID         for (Long ruleId : ruleIds) {             dynamicCouponRule.setRuleFromDatabase(ruleId); // 从数据库设置规则             rules.register(dynamicCouponRule); // 注册规则         }         rulesEngine.fire(rules, facts); // 执行规则引擎         System.out.println("Final price after discounts: " + cart.getTotalPrice()); // 输出最终价格     } } </code></pre> <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">运行应用程序</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">保存所有文件并在终端中运行以下命令启动应用程序： <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">mvn spring-boot:run </code></pre> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">你应该会看到以下输出： <pre data-tool="mdnice编辑器" style="border-radius: 5px;box-shadow: rgba(0, 0, 0, 0.55) 0px 2px 10px;text-align: left;margin-top: 10px;margin-bottom: 10px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;"><span data-cacheurl="" data-remoteid="" style="display: block;background: none;height: 30px;width: 100%;background-size: 40px;background-repeat: no-repeat;background-color: #282c34;margin-bottom: -7px;border-radius: 5px;background-position: 10px 10px;background-image: url(" https: mmbiz.qpic.cn mmbiz_svg n4hwkmwbsvrnjeax6mil2g3mwbiaiuouhzqkof8tlvvq7zjslspfnxcrru39ibzq80y1yqrpaq2xh9vbuwi5vxydd5378xmvq 640?wx_fmt="svg&from=appmsg");""><code style="overflow-x: auto;padding: 16px;color: #abb2bf;padding-top: 15px;background: #282c34;border-radius: 5px;display: -webkit-box;font-family: Consolas, Monaco, Menlo, monospace;font-size: 12px;">Applied 10% discount for total price exceeding 1000 Applied 5% discount for purchasing electronics Final price after discounts: 1071.0 </code></pre> <h1 data-tool="mdnice编辑器" style="border-top-color: rgb(248, 57, 41);margin-top: 30px;margin-bottom: 15px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;align-items: unset;background-attachment: scroll;background-clip: border-box;background-color: unset;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: solid;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 2px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 0px;border-bottom-right-radius: 0px;box-shadow: none;display: flex;flex-direction: unset;float: unset;height: auto;justify-content: center;line-height: 1.5em;overflow-x: unset;overflow-y: unset;text-align: center;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;"><span style="font-size: 20px;color: rgb(255, 255, 255);background-color: rgb(248, 57, 41);line-height: 1.8em;letter-spacing: 0em;align-items: unset;background-attachment: scroll;background-clip: border-box;background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 1px;border-bottom-width: 1px;border-left-width: 1px;border-right-width: 1px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgb(0, 0, 0);border-left-color: rgb(0, 0, 0);border-right-color: rgb(0, 0, 0);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-left-radius: 13px;border-bottom-right-radius: 13px;box-shadow: none;display: block;font-weight: normal;flex-direction: unset;float: unset;height: auto;justify-content: unset;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;overflow-x: unset;overflow-y: unset;padding-top: 3px;padding-bottom: 5px;padding-left: 5px;padding-right: 5px;text-align: left;text-indent: 0em;text-shadow: none;transform: none;width: auto;-webkit-box-reflect: unset;">总结</h1> <p data-tool="mdnice编辑器" style="color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;text-indent: 0em;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 8px;padding-bottom: 8px;padding-left: 0px;padding-right: 0px;">这个示例展示了如何在 Spring Boot 应用程序中集成 Easy Rules 和 MyBatis，以便通过数据库灵活配置优惠券规则。通过这种方式，你可以在不修改代码的情况下添加新的规则。以下是关键点总结： <ol style="list-style-type: decimal;margin-top: 8px;margin-bottom: 8px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 25px;padding-right: 0px;color: rgb(0, 0, 0);" class="list-paddingleft-1"> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;font-weight: normal;"> <strong style="color: rgb(248, 57, 41);font-weight: bold;background-attachment: scroll;background-clip: border-box;background-color: rgba(0, 0, 0, 0);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 3px;border-bottom-width: 3px;border-left-width: 3px;border-right-width: 3px;border-top-color: rgba(0, 0, 0, 0.4);border-bottom-color: rgba(0, 0, 0, 0.4);border-left-color: rgba(0, 0, 0, 0.4);border-right-color: rgba(0, 0, 0, 0.4);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-right-radius: 0px;border-bottom-left-radius: 0px;">数据库配置：使用 MyBatis 和 MySQL 来存储和管理规则。 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;font-weight: normal;"> <strong style="color: rgb(248, 57, 41);font-weight: bold;background-attachment: scroll;background-clip: border-box;background-color: rgba(0, 0, 0, 0);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 3px;border-bottom-width: 3px;border-left-width: 3px;border-right-width: 3px;border-top-color: rgba(0, 0, 0, 0.4);border-bottom-color: rgba(0, 0, 0, 0.4);border-left-color: rgba(0, 0, 0, 0.4);border-right-color: rgba(0, 0, 0, 0.4);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-right-radius: 0px;border-bottom-left-radius: 0px;">动态规则：使用 Easy Rules 的 <code style="background-attachment: scroll;background-clip: border-box;background-color: rgba(27, 31, 35, 0.05);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;margin-top: 0px;margin-bottom: 0px;margin-left: 2px;margin-right: 2px;padding-top: 2px;padding-bottom: 2px;padding-left: 4px;padding-right: 4px;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 3px;border-bottom-width: 3px;border-left-width: 3px;border-right-width: 3px;border-top-color: rgb(0, 0, 0);border-bottom-color: rgba(0, 0, 0, 0.4);border-left-color: rgba(0, 0, 0, 0.4);border-right-color: rgba(0, 0, 0, 0.4);border-top-left-radius: 4px;border-top-right-radius: 4px;border-bottom-right-radius: 4px;border-bottom-left-radius: 4px;overflow-wrap: break-word;font-family: 'Operator Mono', Consolas, Monaco, Menlo, monospace;word-break: break-all;">DynamicRule</code> 类来加载和执行从数据库获取的规则。 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;font-weight: normal;"> <strong style="color: rgb(248, 57, 41);font-weight: bold;background-attachment: scroll;background-clip: border-box;background-color: rgba(0, 0, 0, 0);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 3px;border-bottom-width: 3px;border-left-width: 3px;border-right-width: 3px;border-top-color: rgba(0, 0, 0, 0.4);border-bottom-color: rgba(0, 0, 0, 0.4);border-left-color: rgba(0, 0, 0, 0.4);border-right-color: rgba(0, 0, 0, 0.4);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-right-radius: 0px;border-bottom-left-radius: 0px;">服务层：通过服务层来处理与数据库的交互。 </section></li> <li> <section style="margin-top: 5px;margin-bottom: 5px;color: rgb(53, 53, 53);font-size: 16px;line-height: 1.8em;letter-spacing: 0.04em;text-align: left;font-weight: normal;"> <strong style="color: rgb(248, 57, 41);font-weight: bold;background-attachment: scroll;background-clip: border-box;background-color: rgba(0, 0, 0, 0);background-image: none;background-origin: padding-box;background-position-x: 0%;background-position-y: 0%;background-repeat: no-repeat;background-size: auto;width: auto;height: auto;margin-top: 0px;margin-bottom: 0px;margin-left: 0px;margin-right: 0px;padding-top: 0px;padding-bottom: 0px;padding-left: 0px;padding-right: 0px;border-top-style: none;border-bottom-style: none;border-left-style: none;border-right-style: none;border-top-width: 3px;border-bottom-width: 3px;border-left-width: 3px;border-right-width: 3px;border-top-color: rgba(0, 0, 0, 0.4);border-bottom-color: rgba(0, 0, 0, 0.4);border-left-color: rgba(0, 0, 0, 0.4);border-right-color: rgba(0, 0, 0, 0.4);border-top-left-radius: 0px;border-top-right-radius: 0px;border-bottom-right-radius: 0px;border-bottom-left-radius: 0px;">规则引擎配置：配置规则引擎并注册动态规则。 </section></li> </ol> </section>

Alibaba分布式事务组件Seata TCC模式实战

作者：微信小助手

<article> 1. 什么是TCC TCC 基于分布式事务中的二阶段提交协议实现，它的全称为 Try-Confirm-Cancel，即资源预留（Try）、确认操作（Confirm）、取消操作（Cancel），他们的具体含义如下： <ol style="margin:0px;" class="list-paddingleft-1"> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#df402a;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:decimal;>Try：对业务资源的检查并预留；</li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#df402a;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:decimal;>Confirm：对业务处理进行提交，即 commit 操作，只要 Try 成功，那么该步骤一定成功；</li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#df402a;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:decimal;>Cancel：对业务处理进行取消，即回滚操作，该步骤回对 Try 预留的资源进行释放。</li> </ol> </article> <section style="text-align: center;" nodeleaf=""> <img src="/upload/923b1e71610be7dd5a2772fd5386d1b6.png" class="rich_pages wxw-img" data-ratio="0.6074074074074074" data-s="300,640" data-type="png" data-w="1080" type="block" data-imgfileid="100001388"> </section> <article data-content="[{" type:block,id:4898-1657170593323,name:list-item,data:{version:1,listid:ujpa-1695360830930,listlevel:1,listtype:unordered,style:{lineheight:1.5}},nodes:[{type:text,id:zmm4-1695360797152,leaves:[{text:xa是资源层面的分布式事务，强一致性，在两阶段提交的整个过程中，一直会持有资源的锁。,marks:[{type:bold},{type:color,value:#df402a},{type:backgroundcolor,value:#ffffff}]}]}],state:{}},{type:block,id:6861-1661927008339,name:list-item,data:{version:1,listid:ujpa-1695360830930,listlevel:1,listtype:unordered},nodes:[{type:text,id:8zw5-1695360797152,leaves:[{text:tcc是业务层面的分布式事务，最终一致性，不会一直持有资源的锁。,marks:[{type:bold},{type:color,value:#df402a},{type:backgroundcolor,value:#ffffff}]}]}],state:{}}]> <ul style="margin:0px;" class="list-paddingleft-1"> <li style="white-space:pre-wrap;line-height:1.5;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#df402a;font-weight:bold;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>XA是资源层面的分布式事务，强一致性，在两阶段提交的整个过程中，一直会持有资源的锁。</li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#df402a;font-weight:bold;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>TCC是业务层面的分布式事务，最终一致性，不会一直持有资源的锁。</li> </ul> </article> <section> </section> <article> TCC 是一种侵入式的分布式事务解决方案，以上三个操作都需要业务系统自行实现，对业务系统有着非常大的入侵性，设计相对复杂，但优点是 TCC 完全不依赖数据库，能够实现跨数据库、跨应用资源管理，对这些不同数据访问通过侵入式的编码方式实现一个原子操作，更好地解决了在各种复杂业务场景下的分布式事务问题。 常见开源TCC框架: <ul style="list-style-type: disc;" class="list-paddingleft-1"> <li> <section> Seata TCC </section></li> <li> <section> Hmily </section></li> <li> <section> Tcc-Transaction </section></li> <li> <section> ByteTCC </section></li> <li> <section> EasyTransaction </section></li> </ul> <section> </section> </article> <article> 2. 以用户下单为例 try-commit try 阶段首先进行预留资源，然后在 commit 阶段扣除资源。如下图： <section nodeleaf=""> <img src="/upload/f184f8b4df30988c593484719814ffd8.png" class="rich_pages wxw-img" data-ratio="1.3592814371257484" data-type="png" data-w="501" style="width: 501px;height: 681px;" data-imgfileid="100001390"> </section> try-cancel try 阶段首先进行预留资源，预留资源时扣减库存失败导致全局事务回滚，在 cancel 阶段释放资源。如下图： <section nodeleaf=""> <img src="/upload/8474331e5303fc8e6041450772593a4d.png" class="rich_pages wxw-img" data-ratio="1.3592814371257484" data-type="png" data-w="501" style="width: 501px;height: 681px;" data-imgfileid="100001389"> </section> </article> <section> </section> <article> 3. Seata TCC 模式 一个分布式的全局事务，整体是两阶段提交的模型。全局事务是由若干分支事务组成的，分支事务要满足两阶段提交的模型要求，即需要每个分支事务都具备自己的： <ul style="list-style-type: disc;" class="list-paddingleft-1"> <li> <section> 一阶段 prepare 行为 </section></li> <li> <section> 二阶段 commit 或 rollback 行为 </section></li> </ul> <section nodeleaf=""> <img src="/upload/7053105a755e6e54300c1d5a5e25a11b.png" class="rich_pages wxw-img" data-ratio="0.5475247524752476" data-type="png" data-w="1010" style="width: 870px;height: 451px;" data-imgfileid="100001391"> </section> 在Seata中，AT模式与TCC模式事实上都是两阶段提交的具体实现，他们的区别在于： AT 模式基于支持本地 ACID 事务的关系型数据库： <ul style="margin:0px;" class="list-paddingleft-1"> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#24292e;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>一阶段 prepare 行为：在本地事务中，一并提交业务数据更新和相应回滚日志记录。</li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#24292e;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>二阶段 commit 行为：马上成功结束，自动异步批量清理回滚日志。</li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#24292e;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>二阶段 rollback 行为：通过回滚日志，自动生成补偿操作，完成数据回滚。</li> </ul> 相应的，TCC 模式不依赖于底层数据资源的事务支持： <ul style="margin:0px;" class="list-paddingleft-1"> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#24292e;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>一阶段 prepare 行为：调用自定义的 prepare 逻辑。</li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#24292e;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>二阶段 commit 行为：调用自定义的 commit 逻辑。</li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#24292e;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>二阶段 rollback 行为：调用自定义的 rollback 逻辑。</li> </ul> 简单点概括，SEATA的TCC模式就是手工的AT模式，它允许你自定义两阶段的处理逻辑而不依赖AT模式的undo_log。 <section> </section> </article> <article data-content="[{" type:block,id:b2h0-1695360830953,name:heading,data:{version:1,level:h2},nodes:[{type:text,id:ao4l-1695360797155,leaves:[{text:2.4 seata tcc模式接口如何改造,marks:[{type:bold},{type:fontsize,value:18}]}]}],state:{}},{type:block,id:8511-1661778066124,name:paragraph,data:{version:1},nodes:[{type:text,id:dhe6-1695360797155,leaves:[{text:假设现有一个业务需要同时使用服务 a 和服务 b 完成一个事务操作，我们在服务 a 定义该服务的一个 tcc 接口：,marks:[]}]}],state:{}}]> 4. Seata TCC模式接口如何改造 假设现有一个业务需要同时使用服务 A 和服务 B 完成一个事务操作，我们在服务 A 定义该服务的一个 TCC 接口： <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="typescript"><code>public interface TccActionOne {</code><code>    @TwoPhaseBusinessAction(name = "prepare", commitMethod = "commit", rollbackMethod = "rollback")</code><code>    public boolean prepare(BusinessActionContext actionContext, @BusinessActionContextParameter(paramName = "a") String a);</code><code>    public boolean commit(BusinessActionContext actionContext);</code><code>    public boolean rollback(BusinessActionContext actionContext);</code><code>}</code></pre> </section> <article data-content="[{" type:block,id:5186-1657204029425,name:paragraph,data:{version:1},nodes:[{type:text,id:3m0i-1695360797156,leaves:[{text:同样，在服务 b 定义该服务的一个 tcc 接口：,marks:[]}]}],state:{}}]> 同样，在服务 B 定义该服务的一个 TCC 接口： </article> <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="cs"><code>public interface TccActionTwo {</code><code>    @TwoPhaseBusinessAction(name = "prepare", commitMethod = "commit", rollbackMethod = "rollback")</code><code>    public void prepare(BusinessActionContext actionContext, @BusinessActionContextParameter(paramName = "b") String b);</code><code>    public void commit(BusinessActionContext actionContext);</code><code>    public void rollback(BusinessActionContext actionContext);</code><code>}</code></pre> </section> <article data-content="[{" type:block,id:6556-1657203763728,name:paragraph,data:{version:1},nodes:[{type:text,id:l8ci-1695360797156,leaves:[{text:在业务所在系统中开启全局事务并执行服务 a 和服务 b 的 tcc 预留资源方法：,marks:[]}]}],state:{}}]> 在业务所在系统中开启全局事务并执行服务 A 和服务 B 的 TCC 预留资源方法： </article> <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="typescript"><code>@GlobalTransactional</code><code>public String doTransactionCommit(){</code><code>    //服务A事务参与者</code><code>    tccActionOne.prepare(null,"one");</code><code>    //服务B事务参与者</code><code>    tccActionTwo.prepare(null,"two");</code><code>}</code></pre> </section> <article> 以上就是使用 Seata TCC 模式实现一个全局事务的例子，TCC 模式同样使用 @GlobalTransactional 注解开启全局事务，而服务 A 和服务 B 的 TCC 接口为事务参与者，Seata 会把一个 TCC 接口当成一个 Resource，也叫 TCC Resource。 5. TCC如何控制异常 在 TCC 模型执行的过程中，还可能会出现各种异常，其中最为常见的有空回滚、幂等、悬挂等。TCC 模式是分布式事务中非常重要的事务模式，但是幂等、悬挂和空回滚一直是 TCC 模式需要考虑的问题，Seata 框架在 1.5.1 版本完美解决了这些问题。 <article> 如何处理空回滚 空回滚指的是在一个分布式事务中，在没有调用参与方的 Try 方法的情况下，TM 驱动二阶段回滚调用了参与方的 Cancel 方法。 那么空回滚是如何产生的呢？ <section nodeleaf=""> <img src="/upload/908b3fe021bd5260a30d19b20604d948.png" class="rich_pages wxw-img" data-ratio="0.7925925925925926" data-type="png" data-w="1080" style="width: 620px;height: 491px;" data-imgfileid="100001392"> </section> 如上图所示，全局事务开启后，参与者 A 分支注册完成之后会执行参与者一阶段 RPC 方法，如果此时参与者 A 所在的机器发生宕机，网络异常，都会造成 RPC 调用失败，即参与者 A 一阶段方法未成功执行，但是此时全局事务已经开启，Seata 必须要推进到终态，在全局事务回滚时会调用参与者 A 的 Cancel 方法，从而造成空回滚。 要想防止空回滚，那么必须在 Cancel 方法中识别这是一个空回滚，Seata 是如何做的呢？ Seata 的做法是新增一个 TCC 事务控制表，包含事务的 XID 和 BranchID 信息，在 Try 方法执行时插入一条记录，表示一阶段执行了，执行 Cancel 方法时读取这条记录，如果记录不存在，说明 Try 方法没有执行。 如何处理幂等 幂等问题指的是 TC 重复进行二阶段提交，因此 Confirm/Cancel 接口需要支持幂等处理，即不会产生资源重复提交或者重复释放。 那么幂等问题是如何产生的呢？ </article> <section style="text-align: center;" nodeleaf=""> <img src="/upload/31bf33db9cd14d523f7ad2272c9906da.png" class="rich_pages wxw-img" data-ratio="0.7981481481481482" data-s="300,640" data-type="png" data-w="1080" type="block" data-imgfileid="100001393"> </section> <article> 如上图所示，参与者 A 执行完二阶段之后，由于网络抖动或者宕机问题，会造成 TC 收不到参与者 A 执行二阶段的返回结果，TC 会重复发起调用，直到二阶段执行结果成功。 Seata 是如何处理幂等问题的呢？ 同样的也是在 TCC 事务控制表中增加一个记录状态的字段 status，该字段有 3 个值，分别为： <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang=""><code>tried：1</code><code>committed：2</code><code>rollbacked：3</code></pre> </section> <ol style="margin:0px;" class="list-paddingleft-1"></ol> 二阶段 Confirm/Cancel 方法执行后，将状态改为 committed 或 rollbacked 状态。当重复调用二阶段 Confirm/Cancel 方法时，判断事务状态即可解决幂等问题。 <article> 如何处理悬挂 悬挂指的是二阶段 Cancel 方法比一阶段 Try 方法优先执行，由于允许空回滚的原因，在执行完二阶段 Cancel 方法之后直接空回滚返回成功，此时全局事务已结束，但是由于 Try 方法随后执行，这就会造成一阶段 Try 方法预留的资源永远无法提交和释放了。 那么悬挂是如何产生的呢？ <section nodeleaf=""> <img src="/upload/511ff13516d324ab37740b81da03dedd.png" class="rich_pages wxw-img" data-ratio="0.799074074074074" data-type="png" data-w="1080" style="width: 620px;height: 495px;" data-imgfileid="100001394"> </section> 如上图所示，在执行参与者 A 的一阶段 Try 方法时，出现网路拥堵，由于 Seata 全局事务有超时限制，执行 Try 方法超时后，TM 决议全局回滚，回滚完成后如果此时 RPC 请求才到达参与者 A，执行 Try 方法进行资源预留，从而造成悬挂。 Seata 是怎么处理悬挂的呢？ 在 TCC 事务控制表记录状态的字段 status 中增加一个状态： <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang=""><code>suspended：4</code></pre> </section> <section> </section> 当执行二阶段 Cancel 方法时，如果发现 TCC 事务控制表没有相关记录，说明二阶段 Cancel 方法优先一阶段 Try 方法执行，因此插入一条 status=4 状态的记录，当一阶段 Try 方法后面执行时，判断 status=4 ，则说明有二阶段 Cancel 已执行，并返回 false 以阻止一阶段 Try 方法执行成功。 </article> <article> 6. Spring Cloud Alibaba整合Seata TCC实战 业务场景 用户下单，整个业务逻辑由三个微服务构成： <ul style="margin:0px;" class="list-paddingleft-1"> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#df402a;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>库存服务：对给定的商品扣除库存数量。</li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#df402a;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>订单服务：根据采购需求创建订单。</li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:#df402a;font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>账户服务：从用户账户中扣除余额。</li> </ul> <section nodeleaf=""> <img src="/upload/4e33be4d3443cb7c8e1805a2385fbf85.png" class="rich_pages wxw-img" data-ratio="1.0079260237780714" data-type="png" data-w="757" style="width: 620px;height: 625px;" data-imgfileid="100001395"> </section> 1) 环境准备 <ul style="list-style-type: disc;" class="list-paddingleft-1"> <li> <section> 父pom指定微服务版本 </section></li> </ul> <section style="text-align: center;" nodeleaf=""> <img src="/upload/bb635f7d8928461a739cb132003d90a5.png" class="rich_pages wxw-img" data-ratio="0.16944444444444445" data-s="300,640" data-type="png" data-w="1080" type="block" data-imgfileid="100001396"> </section> <article data-content="[{" type:block,id:4467-1657243647542,name:list-item,data:{version:1,listid:ewrj-1695360830938,listlevel:1,listtype:unordered},nodes:[{type:text,id:wbma-1695360797159,leaves:[{text:启动seata server(tc)端，seata server使用nacos作为配置中心和注册中心,marks:[]}]}],state:{}},{type:block,id:9076-1657243647542,name:list-item,data:{version:1,listid:ewrj-1695360830938,listlevel:1,listtype:unordered},nodes:[{type:text,id:idac-1695360797159,leaves:[{text:启动nacos服务,marks:[]}]}],state:{}}]> <section> </section> <ul style="list-style-type: disc;" class="list-paddingleft-1"> <li> <section> 启动nacos服务 </section></li> <li> <section> 启动Seata Server(TC)端，Seata Server使用nacos作为配置中心和注册中心 </section></li> </ul> </article> <section> </section> 2)  微服务导入seata依赖 spring-cloud-starter-alibaba-seata内部集成了seata，并实现了xid传递 </article> <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="xml"><code></code><code><dependency></code><code>    <groupId>com.alibaba.cloudgroupId></code><code>    <artifactId>spring-cloud-starter-alibaba-seataartifactId></code><code>dependency></code></pre> </section> <article data-content="[{" type:block,id:mhpc-1695360830965,name:paragraph,data:{},nodes:[{type:text,id:gdno-1695360797161,leaves:[{text: 3）微服务application.yml中添加seata配置,marks:[{type:color,value:#df402a},{type:bold}]}]}],state:{}}]>  3）微服务application.yml中添加seata配置 </article> <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="bash"><code>seata:</code><code>  application-id: ${spring.application.name}</code><code>  # seata 服务分组，要与服务端配置service.vgroup_mapping的后缀对应</code><code>  tx-service-group: default_tx_group</code><code>  registry:</code><code>    # 指定nacos作为注册中心</code><code>    type: nacos</code><code>    nacos:</code><code>      application: seata-server</code><code>      server-addr: 127.0.0.1:8848</code><code>      namespace:</code><code>      group: SEATA_GROUP</code><code>  config:</code><code>    # 指定nacos作为配置中心</code><code>    type: nacos</code><code>    nacos:</code><code>      server-addr: 127.0.0.1:8848</code><code>      namespace: 7e838c12-8554-4231-82d5-6d93573ddf32</code><code>      group: SEATA_GROUP</code><code>      data-id: seataServer.properties</code></pre> </section> <article> 注意：请确保client与server的注册中心和配置中心namespace和group一致 4）定义TCC接口 TCC相关注解如下： <ul style="margin:0px;" class="list-paddingleft-1"> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:rgb(0, 0, 0);font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>@LocalTCC 适用于SpringCloud+Feign模式下的TCC，@LocalTCC一定需要注解在接口上 <section> ，此接口可以是寻常的业务接口，只要实现了TCC的两阶段提交对应方法便可 </section></li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:rgb(0, 0, 0);font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;>@TwoPhaseBusinessAction 注解try方法，其中name为当前tcc方法的bean名称，写方法名便可（全局唯一），commitMethod指向提交方法，rollbackMethod指向事务回滚方法。 <section> 指定好三个方法之后，seata会根据全局事务的成功或失败，去帮我们自动调用提交方法或者回滚方法。 </section></li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:rgb(0, 0, 0);font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;> <section> @BusinessActionContextParameter 注解可以将参数传递到二阶段（commitMethod/rollbackMethod）的方法。 </section></li> </ul> </article> </article> </article> </article> <article data-content="[{" type:block,id:b2h0-1695360830953,name:heading,data:{version:1,level:h2},nodes:[{type:text,id:ao4l-1695360797155,leaves:[{text:2.4 seata tcc模式接口如何改造,marks:[{type:bold},{type:fontsize,value:18}]}]}],state:{}},{type:block,id:8511-1661778066124,name:paragraph,data:{version:1},nodes:[{type:text,id:dhe6-1695360797155,leaves:[{text:假设现有一个业务需要同时使用服务 a 和服务 b 完成一个事务操作，我们在服务 a 定义该服务的一个 tcc 接口：,marks:[]}]}],state:{}}]> <article> <article> <article> <ul style="margin:0px;" class="list-paddingleft-1"> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:rgb(0, 0, 0);font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;> <section> @BusinessActionContextParameter 注解可以将参数传递到二阶段（commitMethod/rollbackMethod）的方法。 </section></li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:rgb(0, 0, 0);font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;> <section> BusinessActionContext 便是指TCC事务上下文 </section></li> </ul> <section> </section> <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="php"><code>/**</code><code> * @author Fox</code><code> *</code><code> * 通过 @LocalTCC 这个注解，RM 初始化的时候会向 TC 注册一个分支事务。</code><code> */</code><code>@LocalTCC</code><code>public interface OrderService {</code><code>    /**</code><code>     * TCC的try方法：保存订单信息，状态为支付中</code><code>     *</code><code>     * 定义两阶段提交，在try阶段通过@TwoPhaseBusinessAction注解定义了分支事务的 resourceId，commit和 cancel 方法</code><code>     *  name = 该tcc的bean名称,全局唯一</code><code>     *  commitMethod = commit 为二阶段确认方法</code><code>     *  rollbackMethod = rollback 为二阶段取消方法</code><code>     *  BusinessActionContextParameter注解传递参数到二阶段中</code><code>     *  useTCCFence seata1.5.1的新特性，用于解决TCC幂等，悬挂，空回滚问题，需增加日志表tcc_fence_log</code><code>     */</code><code>    @TwoPhaseBusinessAction(name = "prepareSaveOrder", commitMethod = "commit", rollbackMethod = "rollback", useTCCFence = true)</code><code>    Order prepareSaveOrder(OrderVo orderVo, @BusinessActionContextParameter(paramName = "orderId") Long orderId);</code><code>    /**</code><code>     *</code><code>     * TCC的confirm方法：订单状态改为支付成功</code><code>     *</code><code>     * 二阶段确认方法可以另命名，但要保证与commitMethod一致</code><code>     * context可以传递try方法的参数</code><code>     *</code><code>     * @param actionContext</code><code>     * @return</code><code>     */</code><code>    boolean commit(BusinessActionContext actionContext);</code><code>    /**</code><code>     * TCC的cancel方法：订单状态改为支付失败</code><code>     * 二阶段取消方法可以另命名，但要保证与rollbackMethod一致</code><code>     *</code><code>     * @param actionContext</code><code>     * @return</code><code>     */</code><code>    boolean rollback(BusinessActionContext actionContext);</code><code>}</code><code>/**</code><code> * @author Fox</code><code> *</code><code> * 通过 @LocalTCC 这个注解，RM 初始化的时候会向 TC 注册一个分支事务。</code><code> */</code><code>@LocalTCC</code><code>public interface StorageService {</code><code>    /**</code><code>     * Try: 库存-扣减数量，冻结库存+扣减数量</code><code>     *</code><code>     * 定义两阶段提交，在try阶段通过@TwoPhaseBusinessAction注解定义了分支事务的 resourceId，commit和 cancel 方法</code><code>     *  name = 该tcc的bean名称,全局唯一</code><code>     *  commitMethod = commit 为二阶段确认方法</code><code>     *  rollbackMethod = rollback 为二阶段取消方法</code><code>     *  BusinessActionContextParameter注解传递参数到二阶段中</code><code>     *</code><code>     * @param commodityCode 商品编号</code><code>     * @param count 扣减数量</code><code>     * @return</code><code>     */</code><code>    @TwoPhaseBusinessAction(name = "deduct", commitMethod = "commit", rollbackMethod = "rollback", useTCCFence = true)</code><code>    boolean deduct(@BusinessActionContextParameter(paramName = "commodityCode") String commodityCode,</code><code>                   @BusinessActionContextParameter(paramName = "count") int count);</code><code>    /**</code><code>     *</code><code>     * Confirm: 冻结库存-扣减数量</code><code>     * 二阶段确认方法可以另命名，但要保证与commitMethod一致</code><code>     * context可以传递try方法的参数</code><code>     *</code><code>     * @param actionContext</code><code>     * @return</code><code>     */</code><code>    boolean commit(BusinessActionContext actionContext);</code><code>    /**</code><code>     * Cancel: 库存+扣减数量，冻结库存-扣减数量</code><code>     * 二阶段取消方法可以另命名，但要保证与rollbackMethod一致</code><code>     *</code><code>     * @param actionContext</code><code>     * @return</code><code>     */</code><code>    boolean rollback(BusinessActionContext actionContext);</code><code>}</code><code>/**</code><code> * @author Fox</code><code> *</code><code> * 通过 @LocalTCC 这个注解，RM 初始化的时候会向 TC 注册一个分支事务。</code><code> */</code><code>@LocalTCC</code><code>public interface AccountService {</code><code>    /**</code><code>     * 用户账户扣款</code><code>     *</code><code>     * 定义两阶段提交，在try阶段通过@TwoPhaseBusinessAction注解定义了分支事务的 resourceId，commit和 cancel 方法</code><code>     *  name = 该tcc的bean名称,全局唯一</code><code>     *  commitMethod = commit 为二阶段确认方法</code><code>     *  rollbackMethod = rollback 为二阶段取消方法</code><code>     *</code><code>     * @param userId</code><code>     * @param money 从用户账户中扣除的金额</code><code>     * @return</code><code>     */</code><code>    @TwoPhaseBusinessAction(name = "debit", commitMethod = "commit", rollbackMethod = "rollback", useTCCFence = true)</code><code>    boolean debit(@BusinessActionContextParameter(paramName = "userId") String userId,</code><code>                  @BusinessActionContextParameter(paramName = "money") int money);</code><code>    /**</code><code>     * 提交事务，二阶段确认方法可以另命名，但要保证与commitMethod一致</code><code>     * context可以传递try方法的参数</code><code>     *</code><code>     * @param actionContext</code><code>     * @return</code><code>     */</code><code>    boolean commit(BusinessActionContext actionContext);</code><code>    /**</code><code>     * 回滚事务，二阶段取消方法可以另命名，但要保证与rollbackMethod一致</code><code>     *</code><code>     * @param actionContext</code><code>     * @return</code><code>     */</code><code>    boolean rollback(BusinessActionContext actionContext);</code><code>}</code></pre> </section> <section> </section> </article> <article data-content="[{" type:block,id:2639-1657243892913,name:paragraph,data:{version:1},nodes:[{type:text,id:eb2n-1695360797164,leaves:[{text:tcc 幂等、悬挂和空回滚问题如何解决？,marks:[{type:color,value:#df402a}]}]}],state:{}},{type:block,id:8795-1657244433615,name:paragraph,data:{version:1},nodes:[{type:text,id:mjv2-1695360797164,leaves:[{text:tcc 模式中存在的三大问题是幂等、悬挂和空回滚。,marks:[{type:color,value:#df402a}]},{text:在 seata1.5.1 版本中，增加了一张事务控制表，表名是 tcc_fence_log 来解决这个问题。而在@twophasebusinessaction 注解中提到的属性 usetccfence 就是来指定是否开启这个机制，这个属性值默认是 false。,marks:[]}]}],state:{}}]> TCC 幂等、悬挂和空回滚问题如何解决？ TCC 模式中存在的三大问题是幂等、悬挂和空回滚。在 Seata1.5.1 版本中，增加了一张事务控制表，表名是 tcc_fence_log 来解决这个问题。而在@TwoPhaseBusinessAction 注解中提到的属性 useTCCFence 就是来指定是否开启这个机制，这个属性值默认是 false。 </article> <article data-content="[{" type:block,id:8388-1657244433615,name:paragraph,data:{version:1},nodes:[{type:text,id:jyrq-1695360797164,leaves:[{text:5）微服务增加tcc_fence_log日志表,marks:[{type:bold},{type:color,value:#df402a}]}]}],state:{}}]> 5）微服务增加tcc_fence_log日志表 </article> <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="sql"><code># tcc_fence_log 建表语句如下（MySQL 语法）</code><code>CREATE TABLE IF NOT EXISTS `tcc_fence_log`</code><code>(</code><code>    `xid`           VARCHAR(128)  NOT NULL COMMENT 'global id',</code><code>    `branch_id`     BIGINT        NOT NULL COMMENT 'branch id',</code><code>    `action_name`   VARCHAR(64)   NOT NULL COMMENT 'action name',</code><code>    `status`        TINYINT       NOT NULL COMMENT 'status(tried:1;committed:2;rollbacked:3;suspended:4)',</code><code>    `gmt_create`    DATETIME(3)   NOT NULL COMMENT 'create time',</code><code>    `gmt_modified`  DATETIME(3)   NOT NULL COMMENT 'update time',</code><code>    PRIMARY KEY (`xid`, `branch_id`),</code><code>    KEY `idx_gmt_modified` (`gmt_modified`),</code><code>    KEY `idx_status` (`status`)</code><code>) ENGINE = InnoDB</code><code>DEFAULT CHARSET = utf8mb4;</code></pre> </section> </article> <article> 6）TCC接口的业务实现 参考课堂代码 7）在全局事务发起者中添加@GlobalTransactional注解 核心代码 </article> <section class="code-snippet__fix code-snippet__js"> <ul class="code-snippet__line-index code-snippet__js"> </ul> <pre class="code-snippet__js" data-lang="ruby"><code>@GlobalTransactional(name="createOrder",rollbackFor=Exception.class)</code><code>public Order saveOrder(OrderVo orderVo) {</code><code>    log.info("=============用户下单=================");</code><code>    log.info("当前 XID: {}", RootContext.getXID());</code><code>    //获取全局唯一订单号  测试使用</code><code>    Long orderId = UUIDGenerator.generateUUID();</code><code>    //阶段一：创建订单</code><code>    Order order = orderService.prepareSaveOrder(orderVo,orderId);</code><code>    //扣减库存</code><code>    storageFeignService.deduct(orderVo.getCommodityCode(), orderVo.getCount());</code><code>    //扣减余额</code><code>    accountFeignService.debit(orderVo.getUserId(), orderVo.getMoney());</code><code>    return order;</code><code>}</code></pre> </section> </article> <article data-content="[{" type:block,id:da7m-1695360830967,name:paragraph,data:{},nodes:[{type:text,id:vnbj-1695360797165,leaves:[{text:8）测试分布式事务是否生效,marks:[{type:color,value:#df402a},{type:bold}]}]}],state:{}},{type:block,id:4039-1661780592020,name:list-item,data:{version:1,listid:tixx-1695360830941,listlevel:1,listtype:unordered},nodes:[{type:text,id:j67r-1695360797165,leaves:[{text:分布式事务成功，模拟正常下单、扣库存，扣余额,marks:[]}]}],state:{index:1}},{type:block,id:4743-1661780592020,name:list-item,data:{version:1,listid:tixx-1695360830941,listlevel:1,listtype:unordered},nodes:[{type:text,id:nyxj-1695360797165,leaves:[{text:分布式事务失败，模拟下单扣库存成功、扣余额失败，事务是否回滚,marks:[]}]}],state:{}}]> 8）测试分布式事务是否生效 <ul style="margin:0px;" class="list-paddingleft-1"> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:rgb(0, 0, 0);font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;> <section> 分布式事务成功，模拟正常下单、扣库存，扣余额 </section></li> <li style="white-space:pre-wrap;line-height:1.75;font-size:14px;text-align:left;list-style-position:inside;word-break:break-word;color:rgb(0, 0, 0);font-weight:normal;font-style:normal;text-decoration:none;background-color:rgba(0, 0, 0, 0);font-family:" microsoft yahei, stxihei;list-style-type:disc;> <section> 分布式事务失败，模拟下单扣库存成功、扣余额失败，事务是否回滚 </section></li> </ul> </article> </article>

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