How to Build Hibernate SessionFactory from Service Registry

In Hibernate, it was often to build a SessionFactoryand pull out a Session as follows:

SessionFactory sessionFactory = new Configuration().configure().buildSessionFactory();
Session session = sessionFactory.openSession();

However, since Hibernate 4.x, this approach is deprecated. According to Hibernate 4 API docs, the Configuration class’ buildSessionFactory() method is deprecated and it recommends developers to use the buildSessionFactory(ServiceRegistry) instead. Here is the new recommended code snippet that builds the SessionFactorybased on a ServiceRegistry and obtains the Session:

Configuration configuration = new Configuration().configure();
ServiceRegistryBuilder registry = new ServiceRegistryBuilder();
registry.applySettings(configuration.getProperties());
ServiceRegistry serviceRegistry = registry.buildServiceRegistry();
SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry);

Session session = sessionFactory.openSession();

The Configuration class’ configure() method loads mappings and properties from the convention resource file hibernate.cfg.xml which should be present in the classpath. It’s also very common to create a separate utility class for building the SessionFactoryas follows:

package net.codejava.hibernate;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;

public class HibernateUtil {

	private static SessionFactory sessionFactory;

	public static SessionFactory getSessionFactory() {
		if (sessionFactory == null) {
			Configuration configuration = new Configuration().configure();
			ServiceRegistryBuilder registry = new ServiceRegistryBuilder();
			registry.applySettings(configuration.getProperties());
			ServiceRegistry serviceRegistry = registry.buildServiceRegistry();
			
			sessionFactory = configuration.buildSessionFactory(serviceRegistry);			
		}
		
		return sessionFactory;
	}

}

NOTE: As of 2014, the above code is deprecated. Here’s new version of the HibernateUtil class that is up-to-date:

package net.codejava.hibernate;

import org.hibernate.SessionFactory;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

public class HibernateUtil {
	private static SessionFactory sessionFactory;
	
	public static SessionFactory getSessionFactory() {
		if (sessionFactory == null) {
			// loads configuration and mappings
			Configuration configuration = new Configuration().configure();
			ServiceRegistry serviceRegistry
				= new StandardServiceRegistryBuilder()
					.applySettings(configuration.getProperties()).build();
			
			// builds a session factory from the service registry
			sessionFactory = configuration.buildSessionFactory(serviceRegistry);			
		}
		
		return sessionFactory;
	}
}

Here’s an example of using this utility class in a Hibernate application:

SessionFactory sessionFactory = HibernateUtil.getSessionFactory();

Session session = sessionFactory.openSession();
session.beginTransaction();
session.save(myObject);

Other Hibernate Tutorials:

• Hibernate Hello World Tutorial for Beginners with Eclipse and MySQL
• Java Hibernate JPA Annotations Tutorial for Beginners
• Hibernate One-to-One Association on Primary Key Annotations Example
• Hibernate One-to-Many Association Annotations Example
• Hibernate Many-to-Many Association Annotations Example
• Hibernate Enum Type Mapping Example
• Hibernate Binary Data and BLOB Mapping Example
• Hibernate Query Language (HQL) Example
• Java Hibernate Reverse Engineering Tutorial with Eclipse and MySQL

About the Author:

Nam Ha Minh is certified Java programmer (SCJP and SCWCD). He began programming with Java back in the days of Java 1.4 and has been passionate about it ever since. You can connect with him on Facebook and watch his Java videos on YouTube.

Attachments:

HibernateUtil.java

[Utility class to build a SessionFactory]

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