我在尝试坚持多对多关系时遇到了异常。任何线索都会非常感激。我正在使用hibernate的@ManyToMany注释，如下所示。
如果我从建筑实体中移除房屋然后坚持下去就可以了。只有在调用persist之前我说构造.setHouses（房屋）时才会出现问题。我有3张桌子：建筑，房屋和建筑房屋。其中Construction_houses使用主键存储建筑和房屋之间的映射。
@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name="construction_houses",
joinColumns={@JoinColumn(name="construction_id", referencedColumnName = "id")},
inverseJoinColumns={@JoinColumn(name="house_id", referencedColumnName = "id")})
private List<House> houses = new ArrayList<>();
例外：
org.hibernate.PropertyAccessException: could not get a field value by reflection getter of com.construction.domain.House.id
javax.persistence.PersistenceException: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of com.construction.domain.House.id
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1763)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1677)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1683)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:1187)
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:483)
at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:291)
at com.sun.proxy.$Proxy46.persist(Unknown Source)
at com.construction.domain.BaseEntity.persist(BaseEntity.java:44)
at com.construction.service.QuizEngineService.generateQuiz(QuizEngineService.java:83)
at com.construction.service.QuizEngineService$$FastClassBySpringCGLIB$$e2bbd45a.invoke(<generated>)
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:717)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99)
at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:267)
at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:653)
at com.construction.service.QuizEngineService$$EnhancerBySpringCGLIB$$4b29f50c.generateQuiz(<generated>)
at com.construction.service.QuizEngineServiceTest.testQuizEngineServiceMustNotBeNull(QuizEngineServiceTest.java:27)
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:483)
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.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:73)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:73)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:217)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:83)
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$2.evaluate(ParentRunner.java:229)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:68)
at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:163)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.runTestClass(JUnitTestClassExecuter.java:86)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.execute(JUnitTestClassExecuter.java:49)
at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassProcessor.processTestClass(JUnitTestClassProcessor.java:69)
at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:48)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
at org.gradle.messaging.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)
at org.gradle.messaging.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)
at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)
at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:105)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)
at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
at org.gradle.messaging.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:355)
at org.gradle.internal.concurrent.DefaultExecutorFactory$StoppableExecutorImpl$1.run(DefaultExecutorFactory.java:64)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:744)
Caused by: org.hibernate.PropertyAccessException: could not get a field value by reflection getter of com.construction.domain.House.id
at org.hibernate.property.DirectPropertyAccessor$DirectGetter.get(DirectPropertyAccessor.java:60)
at org.hibernate.tuple.entity.AbstractEntityTuplizer.getIdentifier(AbstractEntityTuplizer.java:346)
at org.hibernate.persister.entity.AbstractEntityPersister.getIdentifier(AbstractEntityPersister.java:4746)
at org.hibernate.persister.entity.AbstractEntityPersister.isTransient(AbstractEntityPersister.java:4465)
at org.hibernate.engine.internal.ForeignKeys.isTransient(ForeignKeys.java:243)
at org.hibernate.event.internal.AbstractSaveEventListener.getEntityState(AbstractSaveEventListener.java:511)
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:116)
at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:801)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:794)
at org.hibernate.jpa.event.internal.core.JpaPersistEventListener$1.cascade(JpaPersistEventListener.java:97)
at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:350)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:293)
at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161)
at org.hibernate.engine.internal.Cascade.cascadeCollectionElements(Cascade.java:379)
at org.hibernate.engine.internal.Cascade.cascadeCollection(Cascade.java:319)
at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:296)
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:137)
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:811)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:784)
at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:789)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:1181)
... 67 more
Caused by: java.lang.IllegalArgumentException: Can not set java.lang.Long field com.construction.domain.House.id to [Ljava.lang.Object;
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:167)
at sun.reflect.UnsafeFieldAccessorImpl.throwSetIllegalArgumentException(UnsafeFieldAccessorImpl.java:171)
at sun.reflect.UnsafeFieldAccessorImpl.ensureObj(UnsafeFieldAccessorImpl.java:58)
at sun.reflect.UnsafeObjectFieldAccessorImpl.get(UnsafeObjectFieldAccessorImpl.java:36)
at java.lang.reflect.Field.get(Field.java:387)
at org.hibernate.property.DirectPropertyAccessor$DirectGetter.get(DirectPropertyAccessor.java:57)
... 96 more
House.java
@Entity
@Table(name = "houses")
public class House {
@Id
@SequenceGenerator(name = "house_sequence", sequenceName = "house_sequence", allocationSize = 1)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "house_sequence")
private Long id;
@Column(name = "description")
private String description;
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
}
Construction.java
@Entity
@Table(name = "constructions")
public class Construction {
@Id
@SequenceGenerator(name = "construction_sequence", sequenceName = "construction_sequence", allocationSize = 1)
@GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "construction_sequence")
private Long id;
@Column(name = "is_completed")
@Type(type = "yes_no")
private boolean isCompleted;
@ManyToMany(cascade = CascadeType.ALL)
@JoinTable(name="construction_houses",
joinColumns={@JoinColumn(name="construction_id", referencedColumnName = "id")},
inverseJoinColumns={@JoinColumn(name="house_id", referencedColumnName = "id")})
private List<House> houses = new ArrayList<>();
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public boolean isCompleted() {
return isCompleted;
}
public void setCompleted(boolean isCompleted) {
this.isCompleted = isCompleted;
}
public List<House> getHouses() {
return houses;
}
public void setHouses(List<House> houses) {
this.houses = houses;
}
}
答案 0 :(得分：2)
stacktrace声明：
无法将java.lang.Long字段com.construction.domain.House.id设置为[Ljava.lang.Object;
不幸的是，该消息不仅针对setter，也针对getter。
因此，该消息告诉您它尝试读取字段House.id不是针对类型为House的对象，而是针对类型为Object[]的对象。
您的houses似乎不是House个对象的列表，而是数组的列表 - 或者它至少包含一个这样的数组。
如果您在坚持施工前致电System.out.println(construction.getHouses());，您会发现以下内容：... [Ljava.lang.Object;@ ......