How to retrieve the datasource used by a persistence unit programmatically

Question

...without actually reading and parsing the persistence.xml

I can retrieve the name of the persistence unit of an EntityManager using the p

Answer 1

I'm using Hibernate 5.0.x

This is how I'm getting a connection from the persistence pool:

import org.hibernate.engine.jdbc.connections.spi.ConnectionProvider;
import org.hibernate.jpa.internal.EntityManagerFactoryImpl;

public Connection getConnection(EntityManagerFactory emf) throws SQLException
{
    final EntityManagerFactoryImpl hibernateEmf = (EntityManagerFactoryImpl) emf;
    return hibernateEmf.getSessionFactory().getServiceRegistry().getService(ConnectionProvider.class).getConnection();
}

The emf parameter is JPA's standard javax.persistence.EntityManagerFactory, typically acquired globally using:

emf = Persistence.createEntityManagerFactory("persistence-unit-name");

or by injection:

@PersistenceUnit(unitName="persistence-unit-name")
EntityManagerFactory emf;