public class HibernateUntil {

     private static Configuration cfg=new Configuration().configure();

    private static SessionFactory factory=cfg.buildSessionFactory();

     //1.方法返回session  静态成员变量不能直接使用非静态成员

     //Session依赖于Session工厂，工厂依赖于Configure

     public static Session getSession(){

       return factory.openSession();

     }

     //2.关闭session

     public static void closeSession(){

         getSession().close();

     }

 @Test

     public void testhibernate() {

         deleteStudent();//删除学生

     }

  private void deleteStudent() {

       Session session= HibernateUntil.getSession();

       Student student=new Student();

       student.setSid();

       //开启事务

       Transaction tx=session.beginTransaction();

       session.delete(student);

       tx.commit();

       HibernateUntil.closeSession();

         System.out.println("success  ok");

     }