“MyBatis-Plus（简称 MP）是一个 MyBatis 的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生”

集成MyBatisPlus后，可以通过继承类的方式，在Service、Dao、Mapper中实现简单逻辑以及SQL，省去了大部分简单代码的工作，的提高开发效率。
本文记录了Springboot项目快速整合MyBatisPlus的过程。

使用的环境如下

环境	版本
系统	macOS 10.15.4
JDK	8
Maven	3

搭建Springboot

Springboot的搭建过程 ~~懒的写~~ 不在本文记录…
使用的是2.3.2.RELEASE的版本

Maven依赖

引入MyBatisPlus依赖

<dependencies>
    <!--Springboot-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
        <version>2.3.2.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <version>2.3.2.RELEASE</version>
    </dependency>
    <!--Lombok-->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.8</version>
    </dependency>
    <!--MySQL-->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.49</version>
    </dependency>
    <!--MybatisPlus-->
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus-boot-starter</artifactId>
        <version>3.4.3</version>
    </dependency>
    <dependency>
        <groupId>com.baomidou</groupId>
        <artifactId>mybatis-plus</artifactId>
        <version>3.4.3</version>
    </dependency>
</dependencies>

application.yml

配置文件中要给MyBatisPlus加上相关的参数

1 2	mybatis-plus: mapper-locations: classpath:mappers//Mapper.xml

Springboot启动类

在启动类上添加
@MapperScan(value = "com.blackteachan.demo.dao")
来扫描Dao

@SpringBootApplication
@MapperScan(value = "com.blackteachan.demo.dao")
public class DemoApplication {
    
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
    
}

Controller

控制器调用Service没啥好说的
这里的ServerResponse是封装返回给前端用的

@RestController
@RequestMapping("/demo")
public class DemoController {
    
    @Autowired
    private DemoService demoService;
    
    @GetMapping("/{id}")
    public ServerResponse<TableEntity> get(@PathVariable Long id){
        TableEntity tableEntity = demoService.getById(id);
        return ServerResponseUtil.success(tableEntity);
    }
    
    @PostMapping
    public ServerResponse save(TableEntity tableEntity){
        tableEntity.setCreateUser(1L);
        tableEntity.setCreateTime(new Date());
        demoService.save(tableEntity);
        return ServerResponseUtil.success();
    }
    
}

Service

DemoService接口继承MyBatisPlus的IService<T>
IService<T>的T是表的实体类

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public interface DemoService extends IService<TableEntity> {
    
}

ServiceImpl

DemoServiceImpl实现类除了实现DemoService接口外，还要继承MyBatisPlus的ServiceImpl<M, T>
ServiceImpl<M, T>的M是一个继承BaseMapper<T>的Dao，T是表的实体类

@Service
public class DemoServiceImpl extends ServiceImpl<DemoMapper, TableEntity> implements DemoService {
    
}

Dao

DemoMapper接口需要继承MyBatisPlus的BaseMapper<T>
T是表的实体类

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public interface DemoMapper extends BaseMapper<TableEntity> {
    
}

Mapper

Mapper.xml里很空，不需要加东西

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.blackteachan.demo.dao.DemoMapper">
    
</mapper>

实体类

TableEntity的属性和数据库表字段一一对应

@Data
@TableName(value = "t_table")
public class TableEntity implements Serializable {
    
    private static final long serialVersionUID = -3906522870557549136L;
    
    @TableId(value = "id", type = IdType.AUTO)
    private Long id;
    private String code;
    private String name;
    private Long createUser;
    private Date createDate;
    private Long updateUser;
    private Date updateTime;
    
}

MySQL

非常简单的一张表

CREATE TABLE `t_table` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `code` varchar(20) NOT NULL,
  `name` varchar(50) DEFAULT NULL,
  `create_user` bigint(255) NOT NULL,
  `create_time` datetime NOT NULL,
  `update_user` bigint(20) DEFAULT NULL,
  `update_time` datetime DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

Postman测试

通过Postman工具请求接口，在console里面可以看到数据已经被插入了
调用Post接口：

2021-08-04 15:43:44,360 [http-nio-8888-exec-6] DEBUG com.blackteachan.demo.dao.DemoMapper.insert -[BaseJdbcLogger.java:137]- ==>  Preparing: INSERT INTO t_table ( code, name, create_user, create_time ) VALUES ( ?, ?, ?, ? )
2021-08-04 15:43:44,361 [http-nio-8888-exec-6] DEBUG com.blackteachan.demo.dao.DemoMapper.insert -[BaseJdbcLogger.java:137]- ==> Parameters: CODE_0001(String), 名称(String), 1(Long), 2021-08-04 15:43:44.359(Timestamp)
2021-08-04 15:43:44,363 [http-nio-8888-exec-6] DEBUG com.blackteachan.demo.dao.DemoMapper.insert -[BaseJdbcLogger.java:137]- <==    Updates: 1
2021-08-04 15:44:09,188 [http-nio-8888-exec-7] DEBUG com.blackteachan.demo.dao.DemoMapper.insert -[BaseJdbcLogger.java:137]- ==>  Preparing: INSERT INTO t_table ( code, name, create_user, create_time ) VALUES ( ?, ?, ?, ? )
2021-08-04 15:44:09,189 [http-nio-8888-exec-7] DEBUG com.blackteachan.demo.dao.DemoMapper.insert -[BaseJdbcLogger.java:137]- ==> Parameters: CODE_0002(String), 名称(String), 1(Long), 2021-08-04 15:44:09.187(Timestamp)
2021-08-04 15:44:09,190 [http-nio-8888-exec-7] DEBUG com.blackteachan.demo.dao.DemoMapper.insert -[BaseJdbcLogger.java:137]- <==    Updates: 1

调用Get接口：

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2021-08-04 15:47:58,831 [http-nio-8888-exec-2] DEBUG com.blackteachan.demo.dao.DemoMapper.selectById -[BaseJdbcLogger.java:137]- ==>  Preparing: SELECT id,code,name,create_user,create_time,update_user,update_time FROM t_table WHERE id=?
2021-08-04 15:47:58,831 [http-nio-8888-exec-2] DEBUG com.blackteachan.demo.dao.DemoMapper.selectById -[BaseJdbcLogger.java:137]- ==> Parameters: 1(Long)
2021-08-04 15:47:58,839 [http-nio-8888-exec-2] DEBUG com.blackteachan.demo.dao.DemoMapper.selectById -[BaseJdbcLogger.java:137]- <==      Total: 1

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SpringBoot之路：整合MyBatisPlus