java spring Long[](数组)类型

Question

如果我有下一个代码

/**
 * Spring Data JPA repository for the Event entity.
 */
@Repository
public interface EventRepository extends JpaRepository<Event, Long>{
    @Query("SELECT id, name FROM event WHERE id IN (:ids)")
    List<EventItem> findEvents(@Param("ids") Long[] ids);
}

并且想使用它

Long[] ids = new Long[3];
ids[0] = new Long(1);
ids[1] = new Long(2);
ids[2] = new Long(3);
eventRepository.findEvents(ids);

如何正确使用。我是 Spring 框架的初学者。我想同时获取一些具有特定 id 的记录。

Answer 1

使用 JPA @NamedQuery 即

事件实体

@Entity
@Table(name = "event")
@NamedQuery(name = "Event.fetchEventItem",
        query = "SELECT id, name FROM event WHERE id IN (:ids)"
)
public class Event {
....
}

您的界面

 @Repository
    public interface EventRepository extends JpaRepository<Event, Long>{
        List<EventItem> findEvents(Long[] ids);
    }

接口(interface)实现类

@Repository
@Transactional(readOnly = true)
public class EventRepositoryImpl implements EventRepository {
 @PersistenceContext
 EntityManager entityManager;

     @Override
        public List<EventItem> findEvents(Long[] ids) {
        List<Event> list = new ArrayList<Event>();
         Query query = em.createNamedQuery("SELECT c FROM Country c");
            Query query = entityManager.createNamedQuery("Event.fetchEventItem", Event.class);
            query.setParameter(1, ids);
            list = query.getResultList();

            // Here You can Prapared List<EventItem>

        }


    }