传递给实体的独立实体：配置文件

Question

I've the following two entities:

@Entity
public class Profile implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue
    private int id;

    @OneToOne
    @JoinColumn(nullable = false, name = "USERNAME_FK")
    private RegisteredUser user;

    ...

and

@Entity
public class RegisteredUser implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    private int id;

    @OneToOne
    @JoinColumn(nullable = false, name = "USERNAME_FK")
    private User user;

    @OneToOne(cascade = CascadeType.ALL, mappedBy = "user")
    private Profile profile;
    ...

I'm using "repositories" and hibernate to store entities to the database. I would like that my entities are as much robust as possible by using annotations, but this is only causing me a lot of problems.

Currently, I've the following code:

@Autowired
private RegisteredUserRepository rur;

@Autowired
private UserRepository ur;
...

// Creating a user
User root = new User("root", "1234", "root@root.com");
root.setFirstName("root");
root.setLastName("root");
root = ur.save(root);

Profile profile = new Profile(String.format("%s", root.getFullName()));

RegisteredUser registeredUser = new RegisteredUser(profile);
root.setRegisteredUser(registeredUser);
registeredUser = rur.save(registeredUser);
registeredUser = rur.save(registeredUser); // PROBLEM HERE!

The traceback of the problem is:

Caused by: org.hibernate.PersistentObjectException: detached entity passed to persist: com.mycompany.app.models.Profile
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:139) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:801) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:794) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.jpa.event.internal.core.JpaPersistEventListener$1.cascade(JpaPersistEventListener.java:97) ~[hibernate-entitymanager-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.engine.internal.Cascade.cascadeToOne(Cascade.java:350) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.engine.internal.Cascade.cascadeAssociation(Cascade.java:293) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.engine.internal.Cascade.cascadeProperty(Cascade.java:161) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.engine.internal.Cascade.cascade(Cascade.java:118) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.cascadeAfterSave(AbstractSaveEventListener.java:470) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:295) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:195) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.event.internal.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:138) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.jpa.event.internal.core.JpaPersistEventListener.saveWithGeneratedId(JpaPersistEventListener.java:84) ~[hibernate-entitymanager-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:206) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:149) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:75) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.internal.SessionImpl.firePersist(SessionImpl.java:811) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:784) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.internal.SessionImpl.persist(SessionImpl.java:789) ~[hibernate-core-4.3.11.Final.jar:4.3.11.Final]
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:1181) ~[hibernate-entitymanager-4.3.11.Final.jar:4.3.11.Final]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_40]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_40]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_40]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_40]
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:294) ~[spring-orm-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at com.sun.proxy.$Proxy88.persist(Unknown Source) ~[na:na]
    at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:439) ~[spring-data-jpa-1.9.4.RELEASE.jar:na]
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_40]
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_40]
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_40]
    at java.lang.reflect.Method.invoke(Method.java:497) ~[na:1.8.0_40]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:483) ~[spring-data-commons-1.11.4.RELEASE.jar:na]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.doInvoke(RepositoryFactorySupport.java:468) ~[spring-data-commons-1.11.4.RELEASE.jar:na]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:440) ~[spring-data-commons-1.11.4.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.data.projection.DefaultMethodInvokingMethodInterceptor.invoke(DefaultMethodInvokingMethodInterceptor.java:61) ~[spring-data-commons-1.11.4.RELEASE.jar:na]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:99) ~[spring-tx-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:281) ~[spring-tx-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:96) ~[spring-tx-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) ~[spring-aop-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:136) ~[spring-tx-4.2.5.RELEASE.jar:4.2.5.RELEASE]
    ... 21 common frames omitted

What I was trying to accomplish is that when I try to save the second time the registered user, it would update the tables correctly.

How can I solve this problem? I've seen that it may be because of how I implemented the setters and getters, so there they are:

Getters and setters in the class RegisteredUser :

public Profile getProfile() {
    return profile;
}

public void setProfile(Profile profile) {
    if (sameAsFormer(profile)) {
        return;
    }

    Profile oldProfile = this.profile;
    this.profile = profile;

    if (oldProfile != null) {
        oldProfile.setRegisteredUser(null);
    }

    if (this.profile != null) {
        this.profile.setRegisteredUser(this);
    }
}

Setters and getters in Profile :

public RegisteredUser getRegisteredUser() {
    return user;
}

public void setRegisteredUser(RegisteredUser u) {
    user = u;
}

Answer 1

Id generator is not specified for the RegisteredUser entity, meaning that the generation strategy is assigned (you have to provide the id value before saving).

Because you don't specify id value, the registeredUser instance is considered transient in the second save call as well. Persist operation is cascaded to the associated Profile which has already been saved in the first call with properly auto-generated id (it has @GeneratedValue annotation on its id field) and is thus considered detached in the new transaction.

The easiest solution is to define id generator for RegisteredUser as well:

@Id
@GeneratedValue
private int id;