Hibernate @ManyToMany 单向关系[重复]
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【中文标题】Hibernate @ManyToMany 单向关系[重复]【英文标题】：Hibernate @ManyToMany unidirectional relationship [duplicate] 【发布时间】：2018-01-21 09:09:47 【问题描述】：我想在Account（您可以将其视为学生）实体和Clas-s-room 实体之间实现@ManyToMany 单向。很简单，一个教室可以有很多学生，学生可以有很多教室。我希望它是单向的，因为我希望班级知道它只包含什么学生，学生不必知道他们有什么班级。到目前为止我所拥有的：Clas-s-room.java
@Entity(name = "Clas-s-room")
@Table(name = "clas-s-room")
public class Clas-s-room extends BaseEntity
@Column(name = "clas-s-room_id", nullable = false, length = 20, unique = true)
private String clas-s-roomId;
@Column(name = "module_code", nullable = false, length = 50, unique = true)
private String moduleCode;
@Column(name = "clas-s-room_name", nullable = false, length = 100, unique = true)
private String clas-s-roomName;
@Column(name = "password", nullable = false, length = 45)
private String password;
@ManyToMany(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
@JoinTable(name = "clas-s-room_student",
joinColumns = @JoinColumn(name = "clas-s-room_id"), inverseJoinColumns = @JoinColumn(name = "account_id"))
private Set<Account> students;
Account.java
@Entity(name = "Account")
@Table(name = "account")
public class Account extends BaseEntity
@Column(name = "email", nullable = false, length = 50, unique = true)
private String email;
@Column(name = "username", nullable = false, length = 20, unique = true)
private String username;
@Column(name = "password", nullable = false, length = 45)
private String password;
@Column(name = "sid", nullable = false, length = 20, unique = true)
private String sid;
@OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
@JoinColumn(name = "profile_id", nullable = false)
private Profile profile;
@Column(name = "acc_type", nullable = false, length = 1)
private char accType;
我通过以下代码（使用 Spring JPA）保存它：
clas-s-room.setClas-s-roomId("ABCD123321345");
Set<Account> account = new HashSet<>();
account.add(accountService.findByUsername("abc"));
account.add(accountService.findByUsername("def"));
System.out.println("Size: " + account.size()); //result is 2
clas-s-room.setStudents(account);
clas-s-roomService.insertOrUpdate(clas-s-room);
但我收到以下错误：
PersistentObjectException: detached entity passed to persist: com.peter.uass.model.Account
这是堆栈跟踪：
javax.faces.FacesException: #clas-s-roomBean.createClas-s-room(): org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: com.peter.uass.model.Account; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: com.peter.uass.model.Account
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:118)
at javax.faces.component.UICommand.broadcast(UICommand.java:315)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
at org.glassfish.grizzly.strategies.Abstractiostrategy.fireIOEvent(AbstractIOStrategy.java:112)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
at java.lang.Thread.run(Thread.java:745)
Caused by: javax.faces.el.EvaluationException: org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: com.peter.uass.model.Account; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: com.peter.uass.model.Account
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
... 35 more
Caused by: org.springframework.dao.InvalidDataAccessApiUsageException: detached entity passed to persist: com.peter.uass.model.Account; nested exception is org.hibernate.PersistentObjectException: detached entity passed to persist: com.peter.uass.model.Account
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.convertHibernateAccessException(HibernateJpaDialect.java:299)
at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:244)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:488)
at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:59)
at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:147)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:133)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:57)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:213)
at com.sun.proxy.$Proxy1321.save(Unknown Source)
at com.peter.uass.service.BaseServiceImpl.insertOrUpdate(BaseServiceImpl.java:27)
at com.peter.uass.service.BaseServiceImpl$$FastClassBySpringCGLIB$$dbade7b8.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:738)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:282)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:673)
at com.peter.uass.service.Clas-s-roomService$$EnhancerBySpringCGLIB$$fd4dbc5d.insertOrUpdate(<generated>)
at com.peter.uass.bean.Clas-s-roomBean.createClas-s-room(Clas-s-roomBean.java:61)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at javax.el.ELUtil.invokeMethod(ELUtil.java:332)
at javax.el.BeanELResolver.invoke(BeanELResolver.java:537)
at javax.el.CompositeELResolver.invoke(CompositeELResolver.java:256)
at com.sun.el.parser.AstValue.invoke(AstValue.java:283)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:304)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
... 36 more
Caused by: org.hibernate.PersistentObjectException: detached entity passed to persist: com.peter.uass.model.Account
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:139)
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:797)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:790)
at org.hibernate.jpa.event.internal.core.JpaPersistEventListener$1.cascade(JpaPersistEventListener.java:97)
at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:352)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:295)
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161)
at org.hibernate.engine.internal.Cascade.cascadeCollectionElements(Cascade.java:381)
at org.hibernate.engine.internal.Cascade.cascadeCollection(Cascade.java:321)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:298)
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161)
at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:118)
at org.hibernate.event.internal.AbstractSaveEventListener.cascadeAfterSave(AbstractSaveEventListener.java:460)
at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:294)
at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:194)
at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:125)
at org.hibernate.jpa.event.internal.core.JpaPersistEventListener.saveWithGeneratedId(JpaPersistEventListener.java:84)
at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:206)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:149)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:75)
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:807)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:780)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:785)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:1181)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:298)
at com.sun.proxy.$Proxy1315.persist(Unknown Source)
at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:508)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.data.repository.core.support.RepositoryFactorySupport$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:56)
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)
... 68 more
对此有任何想法吗？我实施的关系有什么问题吗？
【问题讨论】：
可以分享一下accountService的代码吗？ @AmerQarabsa accountService 里面什么都没有，accountService 所做的只是调用 Spring 存储库来保存实体。 在这里查看帖子，***.com/questions/19610608/… 【参考方案1】：如果级联实体没有 ID，则在级联子级上，如果在级联中指定了操作（在您的情况下，您是级联所有操作），它将被级联，但如果实体确实有一个 ID，则意味着实体已被持久化，由于该实体不受管理，因此将被视为分离实体。
在调用服务后，会话将关闭，因此实体将不再处于持久性上下文中，而不是从服务中获取它，而是使用您的存储库获取您的实体。
Autowired
private AccountDao accountDao;//AccoutDao is the jpa repository for the account
clas-s-room.setClas-s-roomId("ABCD123321345");
Set<Account> account = new HashSet<>();
account.add(accountDao.findByUsername("abc"));
account.add(accountDao.findByUsername("def"));
System.out.println("Size: " + account.size()); //result is 2
clas-s-room.setStudents(account);
clas-s-roomService.insertOrUpdate(clas-s-room);
【讨论】：
如果我删除 CascadeType，我得到mysqlNonTransientConnectionException: No operations allowed after statement closed. 错误
解决方案不是删除级联，是的，您将遇到另一个问题，即您正在引用临时实体（未持久化）来持久化实体，直接使用您的存储库而不是服务，这样您就可以将检索到的对象放在同一个会话中以上是关于Hibernate @ManyToMany 单向关系[重复]的主要内容，如果未能解决你的问题，请参考以下文章
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