EntityManager handling

Question

I am new to JPA 2 and I want to find out which are the best practices for handling an EntityManager on RESOURCE_LOCAL and with JTA. From what I have read, I should be able to make a dependency injection, but I do not quite understand how.

I am using EclipseLink as an implementation.

Have you read this link: http://docs.oracle.com/cd/B32110_01/web.1013/b28221/usclient003.htm — melihcelik, Jan 05 '12 at 11:01
What problem are you having exactly? You can inject an EntityManager directly into your code but there are a few gotcha's you have to watch out for. Please edit your question to include the specific error or problem. — Perception, Jan 05 '12 at 11:52
@Perception I am not using EJBs so I do not know how to make those injections. Please advise... — Dragos, Jan 05 '12 at 12:33

score 2 · Accepted Answer · edited May 23 '17 at 12:12

2

To obtain a reference to EntityManager in your bean, use the following annotation:

@PersistenceContext
private EntityManager entityManager;

Or if you are not using EJB:

EntityManagerFactory entityManagerFactory = Persistence.createEntityManagerFactory("myPersistenceUnitName");
EntityManager entityManager = entityManagerFactory.createEntityManager();
//Do some work...
entityManager.close();
entityManagerFactory.close();

See Persistence unit as RESOURCE_LOCAL or JTA? for an explanation of RESOURCE_LOCAL vs JTA.

edited May 23 '17 at 12:12

Community

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answered Jan 05 '12 at 11:04

Andre

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I am not using EJBs. Where and how does the application find the right EntityManager? – Dragos Jan 05 '12 at 12:30
Then you have to use javax.persistence.EntityManagerFactory (answer edited) – Andre Jan 05 '12 at 12:54

EntityManager handling

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