当我使用A JPA Query的getResultList（）时，结果是分离还是管理？

Question

When I have a JPA Query that I call .getResultList(), It gives me back a List of objects. Are the objects in that list managed or detached? That is, do I have to worry about merging or persisting them later if I make changes to them, or will those changes be picked up automatically?

Answer 1

Yes, the objects returned from .getResultList() are managed.

When you made changes on the managed objects, you do not worry about merging as those changes will be picked up by the EntityManager automatically.

The managed objects will become detached when the EntityManager that is used to load that object is close() , clear() or detach() . Detached objects are not manged anymore and you should do merging to let the EntityManager pick up the changes.

Answer 2

如果您当前在事务中，它们将被管理，但如果您不在事务中（例如，如果您已使用TransactionAttributeType.NOT_SUPPORTED或TransactionAttributeType.NEVER注释了您的实体），则不会管理您的实体。

Answer 3

From my experience the getResultList() return values are Attached. That is, you do not have to manually persist them if you make modifications to them within the same transaction.