MybatisPlus使用注解的多对多级联查询方式

DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (
  `id` int(0) NOT NULL AUTO_INCREMENT COMMENT '主键',
  `nickname` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '昵称',
  `birthday` date NOT NULL COMMENT '生日',
  `username` varchar(32) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '用户名',
  `password` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '密码',
  `status` varchar(2) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL DEFAULT '0' COMMENT '状态 ',
  `create_time` datetime(0) NOT NULL DEFAULT CURRENT_TIMESTAMP(0) COMMENT '创建时间',
  `update_time` datetime(0) NOT NULL DEFAULT CURRENT_TIMESTAMP(0) ON UPDATE CURRENT_TIMESTAMP(0) COMMENT '更新时间',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;

INSERT INTO `user` VALUES (1, 'lh', '2022-06-29', '李大', '123456', '0', '2022-06-29 09:02:07', '2022-06-29 09:02:07');
INSERT INTO `user` VALUES (2, 'ww', '2022-06-29', '陈大', '123456', '0', '2022-06-29 13:06:24', '2022-06-29 13:06:24');
INSERT INTO `user` VALUES (3, 'aa', '2022-06-29', '刘达', '123456', '0', '2022-06-29 13:06:48', '2022-06-29 13:06:48');

DROP TABLE IF EXISTS `role`;
CREATE TABLE `role`  (
  `id` int(0) NOT NULL AUTO_INCREMENT COMMENT '主键id',
  `name` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT '角色名称',
  `remark` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '角色描述',
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;

INSERT INTO `role` VALUES (1, '系统管理员', '系统管理员');
INSERT INTO `role` VALUES (2, '数据管理员', '数据管理员');

DROP TABLE IF EXISTS `user_role`;
CREATE TABLE `user_role`  (
  `user_id` int(0) NOT NULL COMMENT '用户id',
  `role_id` int(0) NULL DEFAULT NULL COMMENT '角色id'
) ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;

INSERT INTO `user_role` VALUES (1, 1);
INSERT INTO `user_role` VALUES (1, 2);
INSERT INTO `user_role` VALUES (2, 1);
INSERT INTO `user_role` VALUES (2, 2);
INSERT INTO `user_role` VALUES (3, 1);

@Data
@ApiModel("用户视图模型")
public class UserVo {
    /**
     * 用户编号
     */
    @ApiModelProperty("用户编号")
    private Integer id;
    /**
     * 昵称
     */
    @ApiModelProperty("昵称")
    private String nickname;
    /**
     * 用户名
     */
    @ApiModelProperty("用户名")
    private String username;
    /**
     * 生日
     */
    @ApiModelProperty("生日")
    private LocalDateTime birthday;
    private List<Role> roles;
}

 @Select("select * from user where ${ew.SqlSegment}")
 List<UserVo> getList(@Param("ew") QueryWrapper wrapper);

 /**
     * 根据指定的userId去user和user_role关联表查出该user所属role列表
     * @param userId
     * @return
 */
@Select("select * from role left join user_role on role.id=user_role.role_id  where user_role.user_id=#{userId}")
List<Role> getListByUserId(Integer userId);

 @Select("select * from user where ${ew.SqlSegment}")
    @Results({@Result(column = "id",property = "id"),
    @Result(column = "id",property = "roles",many=@Many(
            select = "com.hxh.basic.project.mapper.RoleMapper.getListByUserId"
    ))
    })
List<UserVo> getList(@Param("ew") QueryWrapper wrapper);

@RunWith(SpringRunner.class)
@SpringBootTest(classes = BasicProjectApplication.class)
public class UserServiceImplTest {
    @Resource
    private UserMapper userMapper;
    @Resource
    private RoleMapper roleMapper;
    @Test
    public void getUserInfo(){
        QueryWrapper<User> wrapper=new QueryWrapper();
        wrapper.eq("id",1);
        List<UserVo> list = userMapper.getList(wrapper);
        System.out.println(list);
    }
}

[UserVo(id=1, nickname=lh, username=李哈, birthday=2022-06-29T00:00, roles=[Role(id=1, name=系统管理员, remark=系统管理员), Role(id=2, name=数据管理员, remark=数据管理员)])]