如果使用Spring数据存储库（Spring 4），如何从持久性上下文中分离实体

Question

I need to detach an entity from persistence context, within a spring-boot application.

I have the following base repository:

interface EntityRepository extends CrudRepository<Entity, Long> 

Obviously this is not offering any detach(..) -operation. I found an answer, which is actually not working for me: SO Post .

I tried the same, but it seems that my entity is not detached(as if im changing any field, it gets still persisted)

Custom Repo:

interface MyCustomEntityRepository {
  void detach(Entity ent)
}

Interface Impl:

class MyCustomEntityRepositoryImpl implements MyCustomEntityRepository{
     @PersistenceContext
     private EntityManager em;

     public void detach(Entity ent) {
         em.detach(ent);
     }
}

But I cant extend EntityRepository with MyCustomEntityReposity , as this results in:

No property detach found for type Entity! I managed to get it compiled without errors, by not extending EntityRepository. Also changin CrudRepository to JpaRepository But still my entity is not getting detached, but in linked post, the QA says, that it is working for him/her. The actual reason for detaching the object, is to be able to perform some validations within an @EntityListener , by checking the currently stored entity in db, with the currently changed entity instance, which should be detached.

Does anyone see some errors or give me a clue, what Im doing wrong ?

Using: Spring-boot(1.4.0-release), Spring 4, JPA

Answer 1

Does anyone see some errors or give me a clue, what Im doing wrong?

Although it is hard to tell, what might be part of your actual problem and what is just sloppy question editing.

1. Your interface does not compile

    interface MyCustomEntityRepository { detach(Entity ent) } 

   should probably be

    interface MyCustomEntityRepository { void detach(Entity ent) } 

2. Your implementation of your custom interface should implement the interface:

    class MyCustomEntityRepositoryImpl { 

   should probably be

    class MyCustomEntityRepositoryImpl implements MyCustomEntityRepository { 

If problems persist, please show the actual code you are using with the actual exception, including the stacktrace.