@Autowired vs @PersistenceContext for EntityManager bean

spring jpa entitymanager
Cosmin Vasii picture Cosmin Vasii · Jul 10, 2015 · Viewed 52.5k times · Source

What is the difference between:

@Autowired
private EntityManager em;

versus:

@PersistenceContext
private EntityManager em;

Both options work in my application, but can I break something by using the @Autowired annotation?

Answer

sashok_bg picture sashok_bg · Jul 10, 2015

@PersistenceContext allows you to specify which persistence unit you want to use. Your project might have multiple data sources connected to different DBs and @PersistenceContext allows you to say which one you want to operate on

check the explanation here: http://www.coderanch.com/t/481448/java-EJB-SCBCD/certification/unitName-PersistenceContext

Related questions

Injecting EntityManager Vs. EntityManagerFactory

A long question, please bear with me. We are using Spring+JPA for a web application. My team is debating over injecting EntityManagerFactory in the GenericDAO (a DAO based on Generics something on the lines provided by APPFUSE, we do …

Read More
EntityManager refresh problem

I'm getting this error from my EntityManager when I call the refresh function. public void saveProduct(Product product) { entityManager.refresh(product); } I heard this could be a bug with Spring/Hibernate, however I'm not sure how to get around this. …

Read More
No transactional EntityManager available - working with JPA Api, error with Hibernate Session

I am trying to unwrap the Hibernate Session from injected EntityManager, as I need to use Hibernate's native Criteria API. When I try to use Criteria i get following exception: Caused by: java.lang.IllegalStateException: No transactional EntityManager available at …

Read More