public class HibernateUtil  {    private static SessionFactory sessionFactory;   //表示构造方法私有化，保证单例模式  private MyHibernateSessionFactory(){          }       /**  * @return 获取会话工厂  */    public static SessionFactory getSessionFactory()    {      if(sessionFactory ==null){    //第一步:读取Hibernate的配置文件  hibernamte.cfg.xml文件      Configuration con=new Configuration().configure();      //第二步:创建服务注册构建器对象，通过配置对象中加载所有的配置信息      ServiceRegistryBuilder regbulider=new ServiceRegistryBuilder().applySettings(con.getProperties());      //创建注册服务      ServiceRegistry reg=regbulider.buildServiceRegistry();      //第三步:创建会话工厂      SessionFactory sessionFactory=con.buildSessionFactory(reg);      return sessionFactory;    }else {        return sessionFactory;    }      }}

public boolean usersLogin(Users u) {                Transaction tx=null;        String hql="";        try {            Session session = MyHibernateSessionFactory.getSessionFactory()                    .getCurrentSession();            hql = "from Users where username=? and password=?";            tx =session.beginTransaction();            Query query = session.createQuery(hql);            query.setParameter(0, u.getUsername());            query.setParameter(1, u.getPassword());            List list = query.list();            tx.commit();            if(list.size() > 0){                return true;            }else {                return false;            }                    } catch (Exception e) {            e.printStackTrace();            return false;        }finally{            if(tx != null){                tx = null;            }        }    }