EntityManagerFactory (Java EE 5 SDK)

javax.persistence Interface EntityManagerFactory

public interface EntityManagerFactory

The EntityManagerFactory interface is used by the application to obtain an application-managed entity manager. When the application has finished using the entity manager factory, and/or at application shutdown, the application should close the entity manager factory. Once an EntityManagerFactory has been closed, all its entity managers are considered to be in the closed state.

从以下版本开始:

Java Persistence 1.0

createEntityManager

EntityManager createEntityManager()

Create a new EntityManager. This method returns a new EntityManager instance each time it is invoked. The isOpen method will return true on the returned instance.

createEntityManager

EntityManager createEntityManager(Map map)

Create a new EntityManager with the specified Map of properties. This method returns a new EntityManager instance each time it is invoked. The isOpen method will return true on the returned instance.

close

void close()

Close the factory, releasing any resources that it holds. After a factory instance is closed, all methods invoked on it will throw an IllegalStateException, except for isOpen, which will return false. Once an EntityManagerFactory has been closed, all its entity managers are considered to be in the closed state.

isOpen

boolean isOpen()

Indicates whether or not this factory is open. Returns true until a call to close has been made.

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