How do I get EntityManager from datasource?
10 Answers
- cast the EntityManager to EntityManagerImpl (the Hibernate implementation)
- call getFactory()
- cast the EntityManagerFactory to HibernateEntityManagerFactory.
- call getSessionFactory() and cast it to SessionFactoryImpl.
- call getConnectionProvider() and cast it to the correct implementation.
How do I get EntityManager from EntityManagerFactory?
Here’s how I would do it (roughly): public class BaseDao{ private static final String PERSISTENCE_UNIT_NAME = “Employee”; private static EntityManagerFactory factory = Persistence. createEntityManagerFactory(PERSISTENCE_UNIT_NAME); public void create(MyEntiy person){ EntityManager em = factory.
Why is EntityManager not thread-safe?
EntityManagerFactory instances are thread-safe. The EntityManager and its associated persistence context are created and destroyed explicitly by the application. They are also used when directly injecting EntityManager instances can’t be done because EntityManager instances are not thread-safe.
How do you get EntityManager in JpaRepository?
We don’t have direct access to the EntityManager in a JpaRepository. Therefore, we need to create our own. Likewise, we can use the @PersistenceUnit annotation, in which case we’ll access the EntityManagerFactory and, from it, the EntityManager.
Should you close EntityManager?
EntityManagerFactory instances are heavyweight objects. Each factory might maintain a metadata cache, object state cache, EntityManager pool, connection pool, and more. If your application no longer needs an EntityManagerFactory , you should close it to free these resources.
Is EntityManager an interface?
Interface EntityManager. Interface used to interact with the persistence context. An EntityManager instance is associated with a persistence context. A persistence context is a set of entity instances in which for any persistent entity identity there is a unique entity instance.
How do I get EntityManager instance?
You can give an object access to an EntityManager instance by using the @PersistenceUnit annotation to inject an EntityManagerFactory , from which you can obtain an EntityManager instance.
How do you find the database DataSource?
Procedure
- From your system administrator, obtain the logical name of the data source to which you need to connect.
- Create a Context object to use in the next step.
- In your application program, use JNDI to get the DataSource object that is associated with the logical data source name.
- Use the DataSource.
Does EntityManager flush commit?
The EntityManager. flush() operation can be used to write all changes to the database before the transaction is committed. By default JPA does not normally write changes to the database until the transaction is committed.
How can I get EntityManager from JPA repository?
What is the difference between session and EntityManager?
Session is a hibernate-specific API, EntityManager is a standardized API for JPA. You can think of the EntityManager as an adapter class that wraps Session (you can even get the Session object from an EntityManager object via the getDelegate() function).
How do I get SQL Server DataSource?
Configuring data source names for Microsoft SQL Server
- Choose Start > Settings > Control Panel.
- Double-click Administrative Tools.
- Double-click Data Sources (ODBC).
- Click Add to display a list of installed ODBC drivers.
- Select SQL Server and click Finish.
- Enter the following:
- Do one of the following: