在Spring JPA中通过分页和排序从多个表中选择

Question

我看到Spring Data中的从多个表中选择已经有了多个表的解决方案。我想知道是否可以在Spring JPA/Data中同时编写具有可分页和排序功能的表的自定义查询。

SELECT s.service_id, s.name, us.rating_id 
FROM services s, 
   ratings r, 
   user_services us
where 
   us.service_id = s.service_id and
   us.rating_id = r.rating_id and
   us.user_id= ?
;

提前谢谢你的帮助。

Answer 1

排序功能受到质疑，但分页是可以使用的。

假设我们有：

@Entity
public class Service {

    @Id
    private Long id;

    private String name;

    //...
}

@Entity
public class UserService {

    @Id
    private Long id;

    @ManyToOne        
    User user;

    @ManyToOne        
    Service service;   

    @ManyToOne        
    Rating rating;   

    //...
}

然后我们创建一个投影：

public interface ServiceRating {
    Long getServiceId();
    String getServiceName();
    Long getRatingId();
}

然后创建一个支持分页的查询方法：

public interface UserServiceRepo extends CrudRepository<UserService, Long> {
    @Query("select s.id as serviceId, s.name as serviceName, us.rating.id as ratingId from UserService us join us.service s where us.user.id = ?1")
    Page<ServiceRating> getServiceRating(Long userId, Pageable pageable);
}

Page<ServiceRating> pages = userServiceRepo.getServiceRating(1L, new PageRequest(0, 10));
assertThat(pages.getContent()).hasSize(10));

Sort sort = new Sort(Sort.Direction.ASC, "serviceName");
userServiceRepo.getServiceRating(1L, new PageRequest(0, 10, sort));