Hibernate中Sessionfactory的获取

        // hibernate3.X读取配置文件并且获取session对象的方式
		Configuration configuration = new Configuration().configure();
		SessionFactory sessionFactory = configuration.buildSessionFactory();
		Session session = sessionFactory.openSession();

        // hibernate4.X读取配置文件并且获取session对象的方式
		Configuration config = new Configuration().configure("/config.xml");
		ServiceRegistry registry = new StandardServiceRegistryBuilder().applySettings(config.getProperties()).build();
		SessionFactory sessionFactory = config.buildSessionFactory(registry);
		Session session = sessionFactory.openSession();

        // hibernate5.X读取配置文件并且获取session对象的方式
		StandardServiceRegistry registry = new StandardServiceRegistryBuilder().configure().build();
		SessionFactory sessionFactory = new MetadataSources(registry).buildMetadata().buildSessionFactory();
		Session session = sessionFactory.openSession();