Use mybatis and dynamic-datasource-spring-boot-starter to dynamically switch data sources to operate databases

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Scenario : Use mybatis and dynamic-datasource-spring-boot-starter to dynamically switch data sources to operate databases.

版本：JDK 1.8,Spring Boot 2.6.3,dynamic-datasource-spring-boot-starter-3.3.2,mybatis-3.5.9。

Source code : https://github.com/baomidou/dynamic-datasource-spring-boot-starter

dynamic-datasource-spring-boot-starter : A starter for quickly integrating multiple data sources based on springboot.

1. The dynamic data source annotation @DS acts on the class

1.1GetDataMapper interface and XML

1.1.1 GetDataMapper interface

@DS("hub_a_db")
@Repository
public interface GetDataMapper {
  List<Map<String, Object>> getData(List<Long> paraList);
}

1.1.2GetDataMapper.xml

<?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.hub.example.load.mapper.GetDataMapper">
  <select id="getData" resultType="java.util.Map">
    select CITY_ID AS "cityId",
    CITY_NAME AS "cityName",
    LAND_AREA AS "landArea",
    POPULATION AS "population",
    GROSS AS "gross",
    CITY_DESCRIBE AS "cityDescribe",
    DATA_YEAR AS "dataYear",
    UPDATE_TIME AS "updateTime"
    from t_city
    WHERE CITY_ID IN
    <foreach collection="list" item="cityId" open="(" separator="," close=")">
        #{cityId}
    </foreach>
  </select>
</mapper>

1.2InsertDataMapper interface and XML

1.2.1InsertDataMapper interface

@DS("hub_b_db")
@Repository
public interface InsertDataMapper {
  void insertData(List<Map<String, Object>> data);
}

1.2.2InsertDataMapper.xml

<?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.hub.example.load.mapper.InsertDataMapper">
  <insert id="insertData" parameterType="java.util.List">
    insert into t_city_01 (CITY_ID,
    CITY_NAME,
    LAND_AREA,
    POPULATION,
    GROSS,
    CITY_DESCRIBE,
    DATA_YEAR,
    UPDATE_TIME)
    values
    <foreach collection="list" item="city" open="" separator="," close="">
        (#{city.cityId},
        #{city.cityName},
        #{city.landArea},
        #{city.population},
        #{city.gross},
        #{city.cityDescribe},
        #{city.dataYear},
        #{city.updateTime})
    </foreach>
  </insert>
</mapper>

2. The dynamic data source annotation @DS acts on the method

2.1 GetAndInsertDataMapper interface

@Repository
public interface GetAndInsertDataMapper {
  @DS("hub_a_db")
  List<Map<String, Object>> getData(List<Long> paraList);
  @DS("hub_b_db")
  void insertData(List<Map<String, Object>> data);
}

2.2GetAndInsertDataMapper.xml

<?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.hub.example.load.mapper.GetAndInsertDataMapper">
  <select id="getData" resultType="java.util.Map">
      select CITY_ID AS "cityId",
      CITY_NAME AS "cityName",
      LAND_AREA AS "landArea",
      POPULATION AS "population",
      GROSS AS "gross",
      CITY_DESCRIBE AS "cityDescribe",
      DATA_YEAR AS "dataYear",
      UPDATE_TIME AS "updateTime"
      from t_city
      WHERE CITY_ID IN
      <foreach collection="list" item="cityId" open="(" separator="," close=")">
          #{cityId}
      </foreach>
  </select>
  <insert id="insertData" parameterType="java.util.List">
      insert into t_city_01 (CITY_ID,
      CITY_NAME,
      LAND_AREA,
      POPULATION,
      GROSS,
      CITY_DESCRIBE,
      DATA_YEAR,
      UPDATE_TIME)
      values
      <foreach collection="list" item="city" open="" separator="," close="">
          (#{city.cityId},
          #{city.cityName},
          #{city.landArea},
          #{city.population},
          #{city.gross},
          #{city.cityDescribe},
          #{city.dataYear},
          #{city.updateTime})
      </foreach>
  </insert>
</mapper>

3. Use DynamicDataSourceContextHolder to operate dynamic data sources

Do not use annotations, use DynamicDataSourceContextHolder to operate dynamic data sources when calling.

3.1 GetAndInsertDataByHolderMapper interface

@Repository
public interface GetAndInsertDataByHolderMapper {
  @DS("hub_a_db")
  List<Map<String, Object>> getData(List<Long> paraList);
  @DS("hub_b_db")
  void insertData(List<Map<String, Object>> data);
}

3.2GetAndInsertDataByHolderMapper.xml

<?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.hub.example.load.mapper.GetAndInsertDataByHolderMapper">
  <select id="getData" resultType="java.util.Map">
      select CITY_ID AS "cityId",
      CITY_NAME AS "cityName",
      LAND_AREA AS "landArea",
      POPULATION AS "population",
      GROSS AS "gross",
      CITY_DESCRIBE AS "cityDescribe",
      DATA_YEAR AS "dataYear",
      UPDATE_TIME AS "updateTime"
      from t_city
      WHERE CITY_ID IN
      <foreach collection="list" item="cityId" open="(" separator="," close=")">
          #{cityId}
      </foreach>
  </select>
  <insert id="insertData" parameterType="java.util.List">
      insert into t_city_01 (CITY_ID,
      CITY_NAME,
      LAND_AREA,
      POPULATION,
      GROSS,
      CITY_DESCRIBE,
      DATA_YEAR,
      UPDATE_TIME)
      values
      <foreach collection="list" item="city" open="" separator="," close="">
          (#{city.cityId},
          #{city.cityName},
          #{city.landArea},
          #{city.population},
          #{city.gross},
          #{city.cityDescribe},
          #{city.dataYear},
          #{city.updateTime})
      </foreach>
  </insert>
</mapper>

4. Test class

4.1 Test class

@Slf4j
@RestController
@RequestMapping("/hub/example/load01")
public class LoadController {
  @Autowired
  private GetDataMapper getDataMapper;
  @Autowired
  private InsertDataMapper insertDataMapper;
  @Autowired
  private GetAndInsertDataMapper getAndInsertDataMapper;
  @Autowired
  private GetAndInsertDataByHolderMapper getAndInsertDataByHolderMapper;
  /**
   * 1.动态数据源注解@DS作用在类上
   * */
  @GetMapping("/load01")
  public Object load01() {
    log.info("测试开始...");
    List<Long> paraList =  Arrays.asList(1L,2L,3L);
    List<Map<String, Object>> data = getDataMapper.getData(paraList);
    insertDataMapper.insertData(data);
    log.info("测试结束...");
    return "执行成功";
  }
  /**
   * 2.动态数据源注解@DS作用在方法上
   * */
  @GetMapping("/load02")
  public Object load02() {
    log.info("测试开始...");
    List<Long> paraList =  Arrays.asList(1L,2L,3L);
    List<Map<String, Object>> data = getAndInsertDataMapper.getData(paraList);
    getAndInsertDataMapper.insertData(data);
    log.info("测试结束...");
    return "执行成功";
  }
  /**
   * 3.使用DynamicDataSourceContextHolder操作动态数据源
   * */
  @GetMapping("/load03")
  public Object load03() {
    log.info("测试开始...");
    //1.使用hub_a_db数据源读数据
    DynamicDataSourceContextHolder.push("hub_a_db");
    List<Long> paraList =  Arrays.asList(1L,2L,3L);
    List<Map<String, Object>> data = getAndInsertDataByHolderMapper.getData(paraList);
    //2.使用hub_b_db数据源写数据
    DynamicDataSourceContextHolder.poll();
    DynamicDataSourceContextHolder.push("hub_b_db");
    getAndInsertDataByHolderMapper.insertData(data);
    log.info("测试结束...");
    return "执行成功";
  }
}

5. Basic configuration

5.1 Configure dynamic data source

spring:
  jackson:
    time-zone: GMT+8
  datasource:
    dynamic:
      primary: hub_a_db
      strict: false
      datasource:
        hub_a_db:
          url: jdbc:mysql://127.0.0.1:3306/hub_a_db
          username: hub_a
          password: 12345678
          driver-class-name: com.mysql.cj.jdbc.Driver
        hub_b_db:
          url: jdbc:mysql://127.0.0.1:3306/hub_b_db
          username: hub_b
          password: 12345678
          driver-class-name: com.mysql.cj.jdbc.Driver
mybatis:
  mapper-locations: classpath*:mapper/**/*.xml
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

5.2 Dynamic data source dependent package

<dependency>
  <groupId>com.baomidou</groupId>
  <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
  <version>3.3.2</version>
</dependency>

5.3 Create table statement

CREATE TABLE t_city (
  CITY_ID BIGINT(16) NOT NULL COMMENT '唯一标识',
  CITY_NAME VARCHAR(64) COLLATE utf8_bin NOT NULL COMMENT '城市名',
  LAND_AREA DOUBLE DEFAULT NULL COMMENT '城市面积',
  POPULATION BIGINT(16) DEFAULT NULL COMMENT '城市人口',
  GROSS DOUBLE DEFAULT NULL COMMENT '生产总值',
  CITY_DESCRIBE VARCHAR(512) COLLATE utf8_bin DEFAULT NULL COMMENT '城市描述',
  DATA_YEAR VARCHAR(16) COLLATE utf8_bin DEFAULT NULL COMMENT '数据年份',
  UPDATE_TIME DATETIME DEFAULT NULL COMMENT '更新时间'
) ENGINE=INNODB DEFAULT CHARSET=utf8 COLLATE=utf8_bin COMMENT='城市信息表';

Above, thanks.

April 18, 2023