您正在使用JPA2吗？
PersistenceUnitUtil有两种方法可用于确定实体的加载状态。
例如，组织和用户之间存在双向的oneToMany / ManyToOne关系。
public void test() { EntityManager em = entityManagerFactory.createEntityManager(); PersistenceUnitUtil unitUtil = em.getEntityManagerFactory().getPersistenceUnitUtil(); em.getTransaction().begin(); Organization org = em.find(Organization.class, 1); em.getTransaction().commit(); Assert.assertTrue(unitUtil.isLoaded(org)); // users is a field (Set of User) defined in Organization entity Assert.assertFalse(unitUtil.isLoaded(org, "users")); initializeCollection(org.getUsers()); Assert.assertTrue(unitUtil.isLoaded(org, "users")); for(User user : org.getUsers()) { Assert.assertTrue(unitUtil.isLoaded(user)); Assert.assertTrue(unitUtil.isLoaded(user.getOrganization())); }}private void initializeCollection(Collection<?> collection) { // works with Hibernate EM 3.6.1-SNAPSHOT if(collection == null) { return; } collection.iterator().hasNext();}
