springboot jpa之返回表中部分字段的处理详解

/**
 * 房间已经预定的时间统计表
 */
public interface RoomOrderTimeRepository extends JpaRepository<RoomOrderTime,Integer>{ 
    @Query("select  new com.ddzrh.dto.RoomOrderTimeOutPut(r.orderTime,COUNT(r.orderTime) )" +
            " from RoomOrderTime as r " +
            " where r.roomTypeId =:roomId"+
            " GROUP BY r.orderTime" )
    List<RoomOrderTimeOutPut> queryRoomOrderTime(@Param("roomId") Integer roomId);  
}

@Data
public class RoomOrderTimeOutPut { 
    private Date orderTime;
    private Long orderNum; 
    public RoomOrderTimeOutPut(Date orderTime, Long orderNum) {
        this.orderTime = orderTime;
        this.orderNum = orderNum;
    }    
}

@Data
@Accessors(chain = true)
@EqualsAndHashCode(callSuper = true)
@Entity
@Table(name = "user")
public class User extends AbstractEntity { 
    @Column(unique = true)
    private String username; 
    private String password; 
    private String nickname; 
    private String email; 
    @Column(name = "org_id")
    private Long orgId; 
    @Column(name = "org_name")
    private String orgName;
}

import lombok.Value; 
/**
 * @author wu qilong
 * @date 2019/4/11
 * @Description: 自定义返回值，字段名称要和User实体类中的一致，加上lombok.@Value注解。
 */
@Value
public class UserDTO { 
    private String username; 
    private String nickname; 
    private String email;
}

/**
 * @author Wu Qilong
 * @date 2019/4/11
 * @Description:
 */
public interface UserRepository extends JpaRepository<User, Long> {
 
    /**
     * 用户名查询
     *
     * @param username
     * @return
     */
    Optional<User> findByUsername(String username);
 
 
    /**
     * 用户名查询
     * @param username
     * @return
     */
    <T> Optional<T> findByUsername(String username, Class<T> type);
}

@RunWith(SpringRunner.class)
@SpringBootTest
public class UoServerApplicationTests { 
    @Autowired
    UserRepository userRepository; 
    @Test
    public void contextLoads() {
        UserDTO userDTO = userRepository.findByUsername("wuqilong", UserDTO.class).get();
        Console.log(userDTO);
    }
}

@Value
public class TjVO { 
    Long orgId; 
    Long registerCount;
}
/**
     * 按机构统计注册人数
     * @param pageable
     * @return
     */
    @Query(value = "select new com.wd.cloud.uoserver.dto.TjVO(u.orgId ,count(u.orgId)) from User u group by orgId")
    Page<TjVO> tjByOrgId(Pageable pageable);

public interface TjDTO { 
    /**
     * 所属机构
     * @return
     */
    Long getOrgId();
    /**
     * 注册时间
     * @return
     */
    String getRegisterDate();
 
    /**
     * 注册数量
     * @return
     */
    String getRegisterCount();
 
    /**
     * 管理员数量 当别名与该getXXX名称不一致时，可以使用该注解调整
     * @return
     */
    @Value("#{target.adminCount}")
    Long getManagerCount(); 
}

 /**
     * 按天统计注册人数
     * @return
     */
    @Query(value = "select DATE_FORMAT(gmt_create,\"%Y-%m-%d\") as registerDate,count(*) as registerCount from user group by registerDate",nativeQuery = true)
    List<TjDTO> tj();
 
    /**
     * 按机构统计注册人数
     * @param pageable  分页
     * @return
     */
    @Query(value = "select org_id as orgId,count(*) as registerCount from user group by orgId",
            countQuery = "select count(*) from user group by org_id", nativeQuery = true)
    Page<TjDTO> tjByOrgId(Pageable pageable);

@RunWith(SpringRunner.class)
@SpringBootTest
public class UoServerApplicationTests { 
    @Autowired
    UserRepository userRepository; 
    @Test
    public void contextLoads() {
        List<TjDTO> tjDTOList = userRepository.tj();
        tjDTOList.forEach(tjDTO -> {
            Console.log("registerDate={},registerCount={}", tjDTO.getRegisterDate(), tjDTO.getRegisterCount());
        });
    }
}

@Component
public class SpecBuilder { 
    @PersistenceContext
    private EntityManager entityManager; 
    public List<Object[]> tj(Long orgId) {
        CriteriaBuilder cb = entityManager.getCriteriaBuilder();
        CriteriaQuery<Object[]> query = cb.createQuery(Object[].class);
        Root<User> root = query.from(User.class);
        //拼接where条件
        List<Predicate> predicateList = new ArrayList<Predicate>();
        if (orgId != null) {
            predicateList.add(cb.equal(root.get("orgId"), orgId));
        }
        //加上where条件
        query.where(ArrayUtil.toArray(predicateList, Predicate.class));
        query.multiselect(root.get("orgId"),
                cb.count(root),
                cb.sum(cb.<Integer>selectCase().when(cb.equal(root.get("userType"), 2), 1).otherwise(0)));
        query.groupBy(root.get("orgId"));
        //最终sql:  select org_id,count(id),sum(case when user_type=2 then 1 else 0 end) from user where org_id=?1 group by org_id;
        TypedQuery<Object[]> typedQuery = entityManager.createQuery(query);
        return typedQuery.getResultList();
    } 
}

@RunWith(SpringRunner.class)
@SpringBootTest
public class UoServerApplicationTests { 
    @Autowired
    SpecBuilder specBuilder;
 
    @Test
    public void contextLoads() {
        List<Object[]> tjDTOList1 = specBuilder.tj(169L);
        tjDTOList1.forEach(tjDTO -> {
            Console.log("orgId={},总人数={},管理员人数={}", tjDTO[0], tjDTO[1], tjDTO[2]);
        });
    }
}