springboot集成Mybatis-plus-join-boot-start详解

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.5.5</version>
</dependency>
<dependency>
    <groupId>com.github.yulichang</groupId>
    <artifactId>mybatis-plus-join-boot-starter</artifactId>
    <version>1.4.13</version>
</dependency>

CREATE TABLE `sys_user` (
                            `id` bigint unsigned NOT NULL AUTO_INCREMENT COMMENT 'id',
                            `dept_id` bigint DEFAULT NULL COMMENT '部门id',
                            `user_name` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL COMMENT '账号',
                            `password` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL DEFAULT '' COMMENT '密码',
                            `nick_name` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL DEFAULT '' COMMENT '昵称',
                            `email` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT '' COMMENT '用户邮箱',
                            `phone_number` varchar(11) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT '' COMMENT '手机号码',
                            `sex` char(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT '0' COMMENT '用户性别（0男 1女）',
                            `avatar` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT '' COMMENT '头像地址',
                            `status` char(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL DEFAULT '0' COMMENT '帐号状态（0正常 1停用）',
                            `remark` varchar(500) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '备注',
                            `deleted` tinyint(1) NOT NULL DEFAULT '0' COMMENT '删除标志',
                            `version` int DEFAULT NULL COMMENT '乐观锁',
                            `create_by` bigint DEFAULT NULL COMMENT '创建人',
                            `create_time` datetime DEFAULT NULL COMMENT '创建时间',
                            `update_by` bigint DEFAULT NULL COMMENT '更新人',
                            `update_time` datetime DEFAULT NULL COMMENT '更新时间',
                            PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ROW_FORMAT=DYNAMIC COMMENT='用户信息';

CREATE TABLE `sys_dept` (
                            `id` bigint NOT NULL AUTO_INCREMENT COMMENT '部门id',
                            `parent_id` bigint DEFAULT '0' COMMENT '父部门id',
                            `dept_name` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT '' COMMENT '部门名称',
                            `order_num` int DEFAULT '0' COMMENT '显示顺序',
                            `status` char(1) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT '0' COMMENT '部门状态（0正常 1停用）',
                            `remark` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci DEFAULT NULL COMMENT '备注',
                            `deleted` tinyint(1) NOT NULL DEFAULT '0' COMMENT '删除标志',
                            `create_by` bigint DEFAULT NULL COMMENT '创建人',
                            `create_time` datetime DEFAULT NULL COMMENT '创建时间',
                            `update_by` bigint DEFAULT NULL COMMENT '更新人',
                            `update_time` datetime DEFAULT NULL COMMENT '更新时间',
                            PRIMARY KEY (`id`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci ROW_FORMAT=DYNAMIC COMMENT='部门信息';

public interface SysUserMapper extends MPJBaseMapper<SysUser> {
}
public interface SysDeptMapper extends MPJBaseMapper<SysDept> {
}

@Service
public class SysUserServiceImpl extends MPJBaseServiceImpl<SysUserMapper, SysUser> implements SysUserService {
@Autowired
private SysUserMapper sysUserMapper;

/**
 * 测试：列表多表联查
 *
 * @return
 */
@Override
public List<SysUser> sysUserList() {
    //构建查询条件
    MPJLambdaWrapper<SysUser> queryWrapper = new MPJLambdaWrapper<>();
    //联查
    queryWrapper.selectAll(SysUser.class)
            .select(SysDept::getDeptName)
            .leftJoin(SysDept.class, SysDept::getId, SysUser::getDeptId);
    //返
    return list(queryWrapper);
}

/**
 * 删除
 *
 * @param id
 * @return
 */
@Override
public Boolean deleteById(Long id) {
    //创建一个删除条件
    DeleteJoinWrapper<SysUser> eq = JoinWrappers.delete(SysUser.class)
            //与dept相连
            .leftJoin(SysDept.class, SysDept::getId, SysUser::getDeptId)
            //根据id删除
            .eq(SysUser::getId, id);
    return deleteJoin(eq);
}
}

public interface SysUserService extends MPJBaseService<SysUser> {
/**
 * 列表 ：多表
 *
 * @return
 */
List<SysUser> sysUserList();

/**
 * 删除
 *
 * @param id
 * @return
 */
Boolean deleteById(Long id);
}

@RestController
@RequestMapping("/sysUser")
public class SysUserController {
    @Autowired
    private SysUserService sysUserService;

    /**
     * 列表 ：多表
     *
     * @return
     */
    @GetMapping("/sysUserList")
    public List<SysUser> sysUserList() {
        return sysUserService.sysUserList();
    }

    /**
     * 删除
     *
     * @param id
     * @return
     */
    @DeleteMapping("/deleteById/{id}")
    public Boolean deleteById(@PathVariable("id") Long id) {
        return sysUserService.deleteById(id);
    }
}