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GitHub：https://github.com/dkbnull/SpringBootDemo
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在 Spring Boot整合MyBatis配置多数据源 文章中，展示了Spring Boot整合Mybatis配置多数据源的方法。那么，如果使用MyBatis Plus，如何配置多数据源呢？

官方文档：https://baomidou.com/pages/a61e1b/

MyBatis Plus连接数据库参考：Spring Boot整合MyBatis Plus连接数据库

0 开发环境

• JDK：1.8
• Spring Boot：2.1.1.RELEASE
• MySQL：5.7.13

1 引入依赖

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.5.4</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
    <version>3.5.2</version>
</dependency>

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.30</version>
    <scope>provided</scope>
</dependency>

2 配置数据源

server:
  port: 8090
spring:
  datasource:
    dynamic:
      primary: master       #设置默认的数据源或者数据源组，默认值即为master
      strict: false         #严格匹配数据源，默认false。true未匹配到指定数据源时抛异常，false使用默认数据源
      datasource:
        master:
          url: jdbc:mysql://127.0.0.1:3306/test_master?characterEncoding=utf8&serverTimezone=GMT%2B8
          username: root
          password: root
          driver-class-name: com.mysql.cj.jdbc.Driver     #3.2.0开始支持SPI可省略此配置
        slave:
          url: jdbc:mysql://127.0.0.1:3306/test_slave?characterEncoding=utf8&serverTimezone=GMT%2B8
          username: root
          password: root
          driver-class-name: com.mysql.cj.jdbc.Driver
#
mybatis-plus:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: cn.wbnull.springbootdemo.entity

3 使用@DS切换数据源

@DS 可以注解在方法上或类上，同时存在就近原则 方法上注解 优先于 类上注解。

注解	结果
没有@DS	默认数据源
@DS(“dsName”)	dsName可以为组名也可以为具体某个库的名称

@DS("slave")
@Service
public class UserInfoService {

    @Autowired
    private UserInfoMapper userInfoMapper;

    public List<UserInfo> query() {
        LambdaQueryWrapper<UserInfo> queryWrapper = new LambdaQueryWrapper<>();

        return userInfoMapper.selectList(queryWrapper);
    }
}

4 测试

直接使用 Spring Boot整合MyBatis配置多数据源 中创建的数据库表

4.1 新建实体类

@Data
public class User implements Serializable {

    private static final long serialVersionUID = 1L;

    @TableId(value = "id", type = IdType.AUTO)
    private int id;
    private String name;
}

@Data
public class UserInfo implements Serializable {

    private static final long serialVersionUID = 1L;

    @TableId(value = "id", type = IdType.AUTO)
    private Integer id;

    @TableField("userCode")
    private String userCode;

    @TableField("userName")
    private String userName;

    private String password;
}

注：这里因为数据库里字段是驼峰式命名，所以使用 @TableField 指定对应的数据库字段名，也可以通过yml配置关闭属性映射

mybatis-plus:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: cn.wbnull.springbootdemo.entity
  configuration:
    map-underscore-to-camel-case: false

4.2 新建Mapper

@Repository
public interface UserMapper extends BaseMapper<User> {

}

@Repository
public interface UserInfoMapper extends BaseMapper<UserInfo> {

}

4.3 新建映射文件

<?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="cn.wbnull.springbootdemo.mapper.UserMapper">

    <!-- 通用查询映射结果 -->
    <resultMap id="BaseResultMap" type="cn.wbnull.springbootdemo.entity.User">
        <id column="id" property="id"/>
        <result column="name" property="name"/>
    </resultMap>

    <!-- 通用查询结果列 -->
    <sql id="Base_Column_List">
        id, name
    </sql>
</mapper>

<?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="cn.wbnull.springbootdemo.mapper.UserInfoMapper">

    <!-- 通用查询映射结果 -->
    <resultMap id="BaseResultMap" type="cn.wbnull.springbootdemo.entity.UserInfo">
        <id column="id" property="id"/>
        <result column="userCode" property="userCode"/>
        <result column="userName" property="userName"/>
        <result column="password" property="password"/>
    </resultMap>

    <!-- 通用查询结果列 -->
    <sql id="Base_Column_List">
        id, userCode, userName, password
    </sql>

</mapper>

4.4 新建Service

@Service
public class UserService {

    @Autowired
    private UserMapper userMapper;

    public List<User> query() {
        LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>();

        return userMapper.selectList(queryWrapper);
    }
}

/**
 * 3使用@DS切换数据源 中已展示过该类
 */
@DS("slave")
@Service
public class UserInfoService {

    @Autowired
    private UserInfoMapper userInfoMapper;

    public List<UserInfo> query() {
        LambdaQueryWrapper<UserInfo> queryWrapper = new LambdaQueryWrapper<>();

        return userInfoMapper.selectList(queryWrapper);
    }
}

4.5 新建Controller

@RestController
@RequestMapping("user")
public class UserController {

    @Autowired
    public UserService userService;

    @PostMapping(value = "query")
    public List<User> query() {
        return userService.query();
    }
}

@RestController
@RequestMapping("userInfo")
public class UserInfoController {

    @Autowired
    public UserInfoService userInfoService;

    @PostMapping(value = "query")
    public List<UserInfo> query() {
        return userInfoService.query();
    }
}

4.6 测试

使用Postman测试，输出结果如下

4.6.1 master select

4.6.2 slave select