我一直在尝试使用hibernate将分离的对象合并到数据库中，但是它将新集合项的所有字段都设置为null。
例如：
Album album = sessionFactory.getCurrentSession().get(Album.class, 32);
...
// Detach and unproxy album, i.e. send to client
Track track = new Track();
track.setName("Freak on a Leash");
track.setLength("2:30");
album.getTracks().add(track);
// send back to server
...
sessionFactory.getCurrentSession().merge(album);
导致约束违规异常，因为我的曲目名称和长度设置为@NotNull。出于某种原因，合并尝试保存新曲目将为空值！
这是为什么？我做错了吗？
编辑：根据要求，这里是完整的堆栈跟踪（以及产生它的代码）：
@Test
public void testWebsiteSectionCascadeDelete() {
WebsiteSection section1 = new WebsiteSection();
section1.setDescription("Section 1");
section1.setCategory(new WebsiteSectionCategory(WebsiteSectionCategory.NEWS));
Website website = new Website();
website.setName("Name");
website.setDescription("Desc");
website.setURL("http://what.com");
website.setSections(Sets.newHashSet(section1));
Integer id = (Integer) sessionFactory.getCurrentSession().save(website);
sessionFactory.getCurrentSession().flush();
sessionFactory.getCurrentSession().clear();
WebsiteSection section2 = new WebsiteSection();
section2.setDescription("Section 2");
section2.setCategory(new WebsiteSectionCategory(WebsiteSectionCategory.ENTERTAINMENT));
website = new Website();
website.setId(id);
website.setSections(Sets.newHashSet(section2));
sessionFactory.getCurrentSession().merge(website);
sessionFactory.getCurrentSession().flush();
sessionFactory.getCurrentSession().clear();
assertThat(website.getSections(), Matchers.hasSize(1));
}
堆栈追踪：
javax.validation.ConstraintViolationException: Validation failed for classes [com.test.domain.WebsiteSection] during persist time for groups [javax.validation.groups.Default, ]
List of constraint violations:[
ConstraintViolationImpl{interpolatedMessage='may not be empty', propertyPath=description, rootBeanClass=class com.test.domain.WebsiteSection, messageTemplate='{org.hibernate.validator.constraints.NotBlank.message}'}
ConstraintViolationImpl{interpolatedMessage='may not be null', propertyPath=category, rootBeanClass=class com.test.domain.WebsiteSection, messageTemplate='{javax.validation.constraints.NotNull.message}'}
]
at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:159)
at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreInsert(BeanValidationEventListener.java:94)
at org.hibernate.action.internal.EntityIdentityInsertAction.preInsert(EntityIdentityInsertAction.java:178)
at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:75)
at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:393)
at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:227)
at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:207)
at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:191)
at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:321)
at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:286)
at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:192)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:125)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:206)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:191)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:114)
at org.hibernate.event.internal.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:90)
at org.hibernate.internal.SessionImpl.fireSaveOrUpdate(SessionImpl.java:735)
at org.hibernate.internal.SessionImpl.saveOrUpdate(SessionImpl.java:727)
at org.hibernate.engine.spi.CascadingAction$5.cascade(CascadingAction.java:258)
at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:399)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:342)
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:208)
at org.hibernate.engine.internal.Cascade.cascadeCollectionElements(Cascade.java:429)
at org.hibernate.engine.internal.Cascade.cascadeCollection(Cascade.java:369)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:345)
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:208)
at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:165)
at org.hibernate.event.internal.AbstractFlushingEventListener.cascadeOnFlush(AbstractFlushingEventListener.java:162)
at org.hibernate.event.internal.AbstractFlushingEventListener.prepareEntityFlushes(AbstractFlushingEventListener.java:153)
at org.hibernate.event.internal.AbstractFlushingEventListener.flushEverythingToExecutions(AbstractFlushingEventListener.java:89)
at org.hibernate.event.internal.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:51)
at org.hibernate.internal.SessionImpl.flush(SessionImpl.java:1240)
at com.test.testWebsiteSectionCascadeDelete(CampaignServiceITest.java:828)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
at org.junit.rules.ExpectedException$ExpectedExceptionStatement.evaluate(ExpectedException.java:168)
at org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:88)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
对于网站，我有以下部分：cascade =“save-update，delete-orphan”