[英]detached entity passed to persist: JPA inheritance
我有一個從Vehicle繼承的類Bus。 這是JPA單表繼承(對於總線,鑒別符列為TYPE:“ B”)。 當我嘗試保持總線時,出現此錯誤。 可能是什么原因? 謝謝
Caused by: org.hibernate.PersistentObjectException: detached entity passed to persist: org.enseirb.it307.tp.entities.VehicleStatus
at org.hibernate.event.internal.DefaultPersistEventListener.onPersist(DefaultPersistEventListener.java:139)
at org.hibernate.internal.SessionImpl.firePersistOnFlush(SessionImpl.java:838)
at org.hibernate.internal.SessionImpl.persistOnFlush(SessionImpl.java:831)
at org.hibernate.engine.spi.CascadingActions$8.cascade(CascadingActions.java:357)
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
導致錯誤的代碼:
//Bus
Bus bus1 = BusTools.getSampleBus1();
createdToulouseOrg.addVehicle(bus1);
logger.info("insert Bus " + bus1);
Vehicle createdBus1 = vehicleDao.insertVehicle(bus1);
insertVehicle方法使用entitymanager.persist
@Override
public Vehicle insertVehicle(Vehicle vehicle) {
entityManager.getTransaction().begin();
entityManager.persist(vehicle);
entityManager.getTransaction().commit();
return vehicle;
}
根據日志,車輛包含與一個或多個VehicleStatus
實體的關聯。
給出“傳遞給持久對象的分離實體”錯誤,因為持久操作也已級聯到VehicleStatus
。
最簡單的解決方法是調用merge
而不是persist
:
@Override
public Vehicle insertVehicle(Vehicle vehicle) {
entityManager.getTransaction().begin();
vehicle = entityManager.merge(vehicle);
entityManager.getTransaction().commit();
return vehicle;
}
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