我正在尝试使用JPA注释和抽象类来设置实体继承。
我们的目标是让DAO通过其扩展与基础对象一起工作,这样我们就可以通过使用不同的实体扩展,切入点和覆盖来实现相同应用程序的突变,而无需更改提供者和管理者。
例如: 基本应用程序堆栈有一个DAO提供程序,它使用抽象的Company实体来持久化所有扩展Company:
的对象@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设置参考:)
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。申请B应该这样做:
@Entity
@Table(name = "company")
public class CompanyDefault extends Company {
private String name;
}
每个应用程序(或UnitTest)都存在一次persistence.xml,因此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>
现在要创建公司,我会执行以下操作:
@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持两次?
我的设置和注释怎么样?
我们想做什么:通过使用抽象类的扩展来保存实体?
非常感谢你的帮助!
修改:
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,已经解决了..只是一个简单的错误复制 - 谷歌结果:
显然必须使用InheritanceType.SINGLE_TABLE
。我会尽快关闭这个。
答案 0 :(得分:2)
按编辑解决2:抱歉打扰你。