java - 具有抽象类的 JPA 实体继承 - ConstrainViolationException

Question

我正在尝试使用 JPA 注释和抽象类设置实体继承。

我们的目标是让 DAO 通过其扩展与基本对象一起工作，以便我们可以通过使用不同的实体扩展、切入点和覆盖来更改同一应用程序，而无需更改提供程序和管理器。

示例:基础应用程序堆栈有一个 DAO 提供程序，它使用抽象 Company 实体来保存扩展 Company 的所有对象:

@Entity
@Inheritance(strategy = InheritanceType.JOINED)
public abstract class Company  extends AbstractPersistable<Long> {

    @Column(unique = true)
    private String register_number;           

    // ...
}

@Component
public class CompanyProvider extends JpaProvider<Company, Long> {
// provides CRUD methods via an EntityManager
}

(JPAProvider 设置引用:)

public abstract class JpaProvider<T, ID extends Serializable> implements JpaRepository<T, ID>, JpaSpecificationExecutor<T>, QueryDslPredicateExecutor<T> {

    @PersistenceContext
    private EntityManager em;

应用程序 A 将公司扩展到 CompanyDefault，添加自己的列，但不更改 DAO。应用程序 B 应该执行相同的操作:

@Entity
@Table(name = "company")
public class CompanyDefault  extends Company {    

    private String name;  

}

persistence.xml 对于每个应用程序(或 UnitTest)都存在一次，因此这应该定义实际的实体:

<persistence ... >
    <persistence-unit name="persistanceUnit"  transaction-type="RESOURCE_LOCAL">

    <class>path.to.CompanyDefault</class>

    </persistence-unit>
</persistence>

现在要创建一家公司，我将执行以下操作:

@Inject
private CompanyProvider companyProvider;    

@Test
public void testAbstractCompany() {
    Company company = new CompanyDefault("123");
    ((CompanyDefault)company).setName("test");

    companyProvider.save(company);
}

令人不满意的结果是 ConstraintVioloationException 告诉我主键有重复的条目:

javax.persistence.PersistenceException: org.hibernate.exception.ConstraintViolationException: could not insert: [...CompanyDefault]
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1215)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1148)
    at org.hibernate.ejb.AbstractEntityManagerImpl.convert(AbstractEntityManagerImpl.java:1154)
    at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:678)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.springframework.orm.jpa.SharedEntityManagerCreator$SharedEntityManagerInvocationHandler.invoke(SharedEntityManagerCreator.java:240)
    at $Proxy37.persist(Unknown Source)
    at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:328)
    at ....JpaProvider.save(JpaProvider.java:287)
    at ....JpaProvider$$FastClassByCGLIB$$2caf68f6.invoke(<generated>)
    at net.sf.cglib.proxy.MethodProxy.invoke(MethodProxy.java:191)
    at org.springframework.aop.framework.Cglib2AopProxy$DynamicAdvisedInterceptor.intercept(Cglib2AopProxy.java:617)
    at ....CompanyProvider$$EnhancerByCGLIB$$d3a45b31.save(<generated>)
    at ....PersonManagerTest.testAbstractCompany(PersonManagerTest.java:111)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:240)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    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:236)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:180)
    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:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.hibernate.exception.ConstraintViolationException: could not insert: [....CompanyDefault]
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:96)
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2454)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2854)
    at org.hibernate.action.EntityIdentityInsertAction.execute(EntityIdentityInsertAction.java:71)
    at org.hibernate.engine.ActionQueue.execute(ActionQueue.java:273)
    at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:320)
    at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:203)
    at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:129)
    at org.hibernate.ejb.event.EJB3PersistEventListener.saveWithGeneratedId(EJB3PersistEventListener.java:69)
    at org.hibernate.event.def.DefaultPersistEventListener.entityIsTransient(DefaultPersistEventListener.java:179)
    at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:135)
    at org.hibernate.event.def.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:61)
    at org.hibernate.impl.SessionImpl.firePersist(SessionImpl.java:808)
    at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:782)
    at org.hibernate.impl.SessionImpl.persist(SessionImpl.java:786)
    at org.hibernate.ejb.AbstractEntityManagerImpl.persist(AbstractEntityManagerImpl.java:672)
    ... 42 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Duplicate entry '8' for key 'PRIMARY'
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:406)
    at com.mysql.jdbc.Util.getInstance(Util.java:381)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1038)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3563)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3495)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1959)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2113)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2693)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2102)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2395)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2313)
    at com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2298)
    at org.hibernate.persister.entity.AbstractEntityPersister.insert(AbstractEntityPersister.java:2437)
    ... 56 more

现在为什么 hibernate 会尝试将同一个实体保存两次？

我的设置和注释怎么样？

我们想要做的事情是否可以做到:通过使用抽象类的扩展来保存实体？

非常感谢您的帮助!

编辑:

如果我直接创建并保存扩展对象，也会发生同样的情况:

@Test
public void testAbstractCompany() {      
    CompanyDefault companyDefault = new CompanyDefault("123");
    companyProvider.save(companyDefault);
}

编辑2 - 已解决:

别介意我的文字墙，它已经解决了..只是复制粘贴谷歌结果的一个简单错误:

显然必须使用InheritanceType.SINGLE_TABLE。我会尽快关闭它。

Answer 1

已按照编辑 2 解决:抱歉打扰您。