MyBatis-plus 从入门到入土

MyBatis-plus 是一款 Mybatis 增强工具，用于简化开发，提高效率。下文使用缩写 mp 来简化表示 MyBatis-plus，本文主要介绍 mp 搭配 Spring Boot 的使用。

注：本文使用的 mp 版本是当前最新的3.4.2，早期版本的差异请自行查阅文档

官方网站：baomidou.com/

快速入门

1. 创建一个Spring Boot项目

2. 导入依赖

<!-- pom.xml -->
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.4.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>mybatis-plus</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mybatis-plus</name>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-configuration-processor</artifactId>
        </dependency>
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.2</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

3. 配置数据库

spring:
 datasource:
       driver-class-name: com.mysql.cj.jdbc.Driver
       url: jdbc:mysql://localhost:3306/yogurt?serverTimezone=Asia/Shanghai
       username: root
       password: root
       
mybatis-plus:
 configuration:
       log-impl: org.apache.ibatis.logging.stdout.StdOutImpl #开启SQL语句打印

4. 创建一个实体类

package com.example.mp.po;
import lombok.Data;
import java.time.LocalDateTime;
@Data
public class User {
    private Long id;
    private String name;
    private Integer age;
    private String email;