java - 无法使用可嵌入 ID 创建新实体

Question

我有一个实体

@Entity
public class EcranChamp {

@EmbeddedId
@AttributeOverrides({ @AttributeOverride(name = "id_ecran", column = @Column(name = 
    "ecran", nullable = false)),
@AttributeOverride(name = "id_champ", column = @Column(name = "champ", nullable = false)) })
EcranChampId id ;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "id_ecran")
Ecran ecran;

@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "id_champ")
Champ champ; 
//getters & setters 

和

@Embeddable
public class EcranChampId implements Serializable {

 @Column(name = "id_champ", nullable = false) 
  private Long id_champ; 
  @Column(name = "id_ecran", nullable = false)  
  private Long id_ecran; 

当我尝试添加新的 EcranChamp

EcranChamp ec = new EcranChamp();
ec.setChamp(c);
ec.setEcran(e);

我有这个错误

org.hibernate.id.IdentifierGenerationException: null id generated for:class com.kepler.portailclient.domain.model.EcranChamp
    at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:107) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.jpa.event.internal.core.JpaPersistEventListener.saveWithGeneratedId(JpaPersistEventListener.java:67) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:189) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:132) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:58) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:783) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:768) ~[hibernate-core-5.2.17.Final.jar:5.2.17.Final]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_161]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_161]
    at org.springframework.orm.jpa.ExtendedEntityManagerCreator$ExtendedEntityManagerInvocationHandler.invoke(ExtendedEntityManagerCreator.java:350) ~[spring-orm-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at com.sun.proxy.$Proxy453.persist(Unknown Source) ~[na:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_161]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_161]
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:305) ~[spring-orm-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at com.sun.proxy.$Proxy453.persist(Unknown Source) ~[na:na]
    at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:490) ~[spring-data-jpa-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_161]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_161]
    at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:377) ~[spring-data-commons-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:200) ~[spring-data-commons-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:629) ~[spring-data-commons-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:593) ~[spring-data-commons-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:578) ~[spring-data-commons-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:59) ~[spring-data-commons-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:294) ~[spring-tx-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:98) ~[spring-tx-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:139) ~[spring-tx-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodInterceptor.invoke(CrudMethodMetadataPostProcessor.java:135) ~[spring-data-jpa-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:92) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.data.repository.core.support.SurroundingTransactionDetectorMethodInterceptor.invoke(SurroundingTransactionDetectorMethodInterceptor.java:61) ~[spring-data-commons-2.0.9.RELEASE.jar:2.0.9.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:185) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:212) ~[spring-aop-5.0.8.RELEASE.jar:5.0.8.RELEASE]
    at com.sun.proxy.$Proxy457.save(Unknown Source) ~[na:na]
    at com.kepler.portailclient.domain.service.GestionEcranServiceImp.ajouterChampEcran(GestionEcranServiceImp.java:64) ~[classes/:na]
    at com.kepler.portailclient.interfaces.web.controller.administration.EcranController.ajouterChampEcran(EcranController.java:93) ~[classes/:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_161]
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_161]
    at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_161]

Answer 1

尝试将 Champ 和 Ecran 放入 Embeddable id 中

@Embeddable
public class EcranChampId implements Serializable {
    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "id_champ")
    Champ champ; 

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "id_ecran")
    Ecran ecran;
    //getters & setters 
}


EcranChamp ec = new EcranChamp();
EcranChampId  id = new EcranChampId();
id.setChamp(c);
id.setEcran(e);
ec.setId(id);

并且您必须在 Ecran 和 Champ 内部使用 @Id @GenerateValue(strategy = GenerationType.IDENTITY)