pom

        <!-- mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <!-- mybatis-plus-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
        </dependency>

        <!-- Dynamic DataSource -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>dynamic-datasource-spring-boot-starter</artifactId>
        </dependency>

application.yaml

我这边直接使用了hikari连接池，当然也可以配成druid

# spring配置
spring: 
  datasource:
    hikari:
      connection-timeout: 30000        # 等待连接池分配连接的最大时长（毫秒），超过这个时长还没可用的连接则发生SQLException， 默认:30秒
      minimum-idle: 5                  # 最小连接数
      maximum-pool-size: 100           # 最大连接数
      auto-commit: true                # 事务自动提交
      idle-timeout: 600000             # 连接超时的最大时长（毫秒），超时则被释放（retired），默认:10分钟
      pool-name: DNA_Hikari_Poll       # 连接池名字
      max-lifetime: 1800000            # 连接的生命时长（毫秒），超时而且没被使用则被释放（retired），默认:30分钟 1800000ms
      connection-test-query: SELECT 1  # 连接测试语句
    dynamic:
      primary: master #设置默认的数据源或者数据源组,默认值即为master
      strict: true #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:
          # 主库数据源
          master:
            driver-class-name: com.mysql.cj.jdbc.Driver
            url: jdbc:mysql://xx:xx/llm-mp?useUnicode=true&zeroDateTimeBehavior=convertToNull&autoReconnect=true&characterEncoding=utf-8&serverTimezone=GMT%2B8&allowMultiQueries=true&rewriteBatchedStatements=true
            username: xx
            password: xx
          # 从库数据源
          slave:
            driver-class-name: com.mysql.cj.jdbc.Driver
            url: jdbc:mysql://xx:xx/enetapp_test?useUnicode=true&zeroDateTimeBehavior=convertToNull&autoReconnect=true&characterEncoding=utf-8&serverTimezone=GMT%2B8&allowMultiQueries=true&rewriteBatchedStatements=true
            username: xx
            password: xx

java代码

以两个数据库的两张表为例

Entity

两张表的映射DTO如下
来自于llm-mp

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("sys_user_role")
public class Role {

    @TableField(value = "user_id")
    private Integer userId;

    @TableField(value = "role_id")
    private Integer roleId;
}

来自于enetapp_test

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("llm_mp_train_data")
public class TrainData {

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

    @TableField("source")
    private Float source;

    @TableField("completion")
    private String completion;
}

Mapper

两个mapper分别对应两个数据库的两张表

public interface RoleMapper extends BaseMapper<Role> {
}

public interface TrainDataMapper extends BaseMapper<TrainData> {
}

Service

接口定义

public interface TrainDataService extends IService<TrainData> {
}
public interface RoleService extends IService<Role> {
}

实现类定义

@Service
@DS("master")
public class RoleServiceImpl extends ServiceImpl<RoleMapper, Role> implements RoleService {
}

/**
 * 多数据源使用时请不要使用lambdaQuery()
 * 不然会导致数据源切换失效
 */
@Service
@DS("slave")
public class TrainDataServiceImpl extends ServiceImpl<TrainDataMapper, TrainData> implements TrainDataService {
}

使用

ambdaQuery()会导致从库切换失败，主库可以随便用lambdaQuery()，因为yaml里面配置了默认数据源primary: master

@Service
@RequiredArgsConstructor
public class TestService {

    private final TrainDataService trainDataService;
    private final RoleService roleService;

    public PageVo<TrainData> login() {
        QueryWrapper<TrainData> wrapper = new QueryWrapper<>();
        wrapper.last("limit 0,100");
        List<TrainData> list = trainDataService.list(wrapper);
        return PageUtil.getPageVo(new PageVo<>(),list);
    }

    public String login2() {
        QueryWrapper<TrainData> wrapper = new QueryWrapper<>();
        wrapper.eq(true,"id",3);
        return trainDataService.getOne(wrapper).getCompletion();
    }
}