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. */@Repositorypublic interface EventRepository extends JpaRepository<Event, Long>{    @Query("SELECT id, name FROM event WHERE id IN (:ids)")    List<EventItem> findEvents(@Param("ids") Long[] ids);}并想要使用它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。我想同时获得一些带有特殊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 {

....

}

您的介面

 @Repository

    public interface EventRepository extends JpaRepository<Event, Long>{

        List<EventItem> findEvents(Long[] ids);

    }

接口实现类

@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>

        }

    }