Question

我正在努力定义实体A和B之间的一对多双向关系，并意识到在持久化A以便B更新A之后应该刷新entityManager。这解释为here

在服务层，而不是重复调用

entityManager.refresh(entity)

在jpaRepository.saveAndFlush（实体）之后，我决定实现EntityListeners。

在将entityManager注入EntityListener时遇到了一些issues 并使用步骤here

解决了相同的问题

总结一下，

@Entity
public class Book {

   @Id
   @GeneratedValue(strategy = GenerationType.AUTO)
   private Long id;

   @ManyToOne(cascade={CascadeType.REFRESH})
   private BookCatalog bookCatalog;

   ...
}

@Entity
public class BookCatalog {
   ....
   @OneToMany(mappedBy="bookCatalog")
   private List<Book> books = new ArrayList<>();
   ....
}

@Component
public class LibraryEntityListener {

 @PostPersist
 @PostUpdate
 public void updateBookCatalog(Book book) {
    EntityManager entityManager = BeanUtil.getBean(EntityManager.class);
    entityManager.refresh(book);
 }
}

@Component
public class BookServiceImpl implements BookService {

  @PersistenceContext
  private EntityManager entityManager;

  @Autowired
  private BookCatalogJpaRepository bookCatalogJpaRepository;

  @Autowired
  private BookJpaRepository bookJpaRepository;

  @Override
  public BookCatalog addBookCatalogToLibrary(BookCatalog bookCatalog) {
   BookCatalog catalog = bookCatalogJpaRepository
        .saveAndFlush(bookCatalog);
   notificationService.notifySubscriberForNewAddition(catalog);
   return catalog;
  }

  @Override
  public Book addBookToTheCatalog(Long bookCatalogId, Book book) {
     BookCatalog bookCatalog = new BookCatalog();
     bookCatalog.setId(bookCatalogId);
     book.setBookCatalog(bookCatalog);
     return bookJpaRepository.saveAndFlush(book);
  }
}

但我在entityManager.refresh（书）;

上得到一个例外

org.hibernate.AssertionFailure: null identifier
	at org.hibernate.engine.spi.EntityKey.<init>(EntityKey.java:51)
	at org.hibernate.internal.AbstractSessionImpl.generateEntityKey(AbstractSessionImpl.java:338)
	at org.hibernate.event.internal.DefaultRefreshEventListener.onRefresh(DefaultRefreshEventListener.java:131)
	at org.hibernate.event.internal.DefaultRefreshEventListener.onRefresh(DefaultRefreshEventListener.java:44)
	at org.hibernate.internal.SessionImpl.fireRefresh(SessionImpl.java:1180)
	at org.hibernate.internal.SessionImpl.refresh(SessionImpl.java:1153)
	at org.hibernate.internal.SessionImpl.refresh(SessionImpl.java:1148)
	at org.hibernate.jpa.spi.AbstractEntityManagerImpl.refresh(AbstractEntityManagerImpl.java:1227)
	at org.hibernate.jpa.spi.AbstractEntityManagerImpl.refresh(AbstractEntityManagerImpl.java:1192)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:298)
	at com.sun.proxy.$Proxy105.refresh(Unknown Source)
	at com.foo.library.repository.LibraryEntityListener.updateBookCatalog(LibraryEntityListener.java:19)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.hibernate.jpa.event.internal.jpa.ListenerCallback.performCallback(ListenerCallback.java:35)
	at org.hibernate.jpa.event.internal.jpa.CallbackRegistryImpl.callback(CallbackRegistryImpl.java:94)
	at org.hibernate.jpa.event.internal.jpa.CallbackRegistryImpl.postCreate(CallbackRegistryImpl.java:63)
	at org.hibernate.jpa.event.internal.core.JpaPostInsertEventListener.onPostInsert(JpaPostInsertEventListener.java:38)
	at org.hibernate.action.internal.EntityIdentityInsertAction.postInsert(EntityIdentityInsertAction.java:156)
	at org.hibernate.action.internal.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:102)
	at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:619)
	at org.hibernate.engine.spi.ActionQueue.addResolvedEntityInsertAction(ActionQueue.java:273)
	at org.hibernate.engine.spi.ActionQueue.addInsertAction(ActionQueue.java:254)
	at org.hibernate.engine.spi.ActionQueue.addAction(ActionQueue.java:299)
	at org.hibernate.event.internal.AbstractSaveEventListener.addInsertAction(AbstractSaveEventListener.java:317)
	at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:272)
	at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:178)
	at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:109)
	at org.hibernate.jpa.event.internal.core.JpaPersistEventListener.saveWithGeneratedId(JpaPersistEventListener.java:67)
	at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:189)
	at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:132)
	at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:58)
	at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:775)
	at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:748)
	at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:753)
	at org.hibernate.jpa.spi.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:1146)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:298)
	at com.sun.proxy.$Proxy105.persist(Unknown Source)
	at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:508)
	at org.springframework.data.jpa.repository.support.SimpleJpaRepository.saveAndFlush(SimpleJpaRepository.java:522)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:504)
	at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:489)
	at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:461)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
	at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:61)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
	at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
	at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
	at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
	at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
	at com.sun.proxy.$Proxy112.saveAndFlush(Unknown Source)
	at com.foo.library.service.impl.BookServiceImpl.addBookToTheCatalog(BookServiceImpl.java:50)
	at com.foo.library.service.BookServiceIntegrationTest.testAddBookToTheCatalog(BookServiceIntegrationTest.java:287)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:75)
	at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:86)
	at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:84)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:252)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:94)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:191)
	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:459)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382)
	at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192)

问题：

saveAndFlush（entity）：这里flush意味着实体在数据库中被刷新（持久化）了吗？在这种情况下，在@PostPersist中，为什么hibernate entityEntry无法获取Book实体的id
如何解决此问题？默认情况下，我需要在持久化上下文后立即刷新实体，而不必在每个save方法之后调用refresh。有没有其他方法可以实现这个目标？
我在这里尝试的是用新创建的书更新BookCatalog。有没有其他方法来实现这一目标？如果我使用merge而不是刷新怎么办？那是对的吗？
如果我找到了使用entityManager.refresh（）实现此方法的方法，那么在事务回滚期间会发生什么？我有一个记录丢失的书的方案。
- 关闭租金
- 将该书标记为缺失
- 为用户输入惩罚
  每个步骤都由JpaRepository操作处理。如果输入惩罚失败，那么出租和预订的entityManager.refresh（）是否会回滚？

Answer 1

来自documentation：

回调方法不得调用EntityManager或Query方法！

相反，如果您确实需要在同一个持久化上下文实例中更新反面，只需将该书添加到目录中：

bookCatalog.getBooks().add(book)

Spring Data JPA - 刷新@PostPersist中的entityManager

1 个答案: