java - Spring Hibernate，尝试获取实体时堆栈溢出

Question

我得到:

java.lang.StackOverflowError at kamienica.dao.ApartmentDaoImpl.findById(ApartmentDaoImpl.java:52) at kamienica.dao.ApartmentDaoImpl.findById(ApartmentDaoImpl.java:52) at kamienica.dao.ApartmentDaoImpl.findById(ApartmentDaoImpl.java:52) (and so on..)

当尝试通过主键获取对象时。

这是 AbstractDAO:

public abstract class AbstractDao<PK extends Serializable, T> {

    private final Class<T> persistentClass;

    @SuppressWarnings("unchecked")
    public AbstractDao() {
        this.persistentClass = (Class<T>) ((ParameterizedType) this.getClass().getGenericSuperclass())
                .getActualTypeArguments()[1];
    }

    @Autowired
    private SessionFactory sessionFactory;

    protected SessionFactory getSessionFactory() {
        return sessionFactory;
    }

    protected Session getSession() {
        return sessionFactory.getCurrentSession();
    }


    @SuppressWarnings("unchecked")
    public T findByPK(PK id) {
        Session session = getSession();
        T out = (T) session.load(persistentClass, id);
        session.close();
        return out;
    }

这是 ApartmentDAO 的实现:

@Repository("apatmentDao")
public class ApartmentDaoImpl extends AbstractDao<Integer, Apartment> implements ApartmentDao {

    public void save(Apartment apatment) {
        persist(apatment);

    }

    @Override
    @SuppressWarnings("unchecked")
    public List<Apartment> getList() {
        Criteria criteria = createEntityCriteria();
        criteria.addOrder(Order.asc("apartmentNumber"));
        return (List<Apartment>) criteria.list();
    }

    @Override
    public void deleteByID(int id) {
        Query query = getSession().createSQLQuery("delete from Apartment where id = :id");
        query.setInteger("id", id);
        query.executeUpdate();
    }

    @Override
    public void update(Apartment apatment) {
        update(apatment);
    }


        @Override
        public Apartment findById(int id) {
// If I put System.out.println(id) here it will print id 
// number until the stack overflow
            Apartment ap = findById(id);
            return ap;
        }

我不知道是什么导致了这个问题。其他方法工作得很好...

Answer 1

您正在递归调用 findById 方法。

     @Override
        public Apartment findById(int id) {
            // Here you're recursively calling findById
            Apartment ap = findById(id);
            return ap;
        }

我想你可以做这样的事情，

        @Override
        public Apartment findById(int id) {
            return findByPK(new Integer(id));
        }

希望这有帮助。