1 /* 
 2      * 根据客户的用户名查找客户信息
 3      */
 4     @Override
 5     public User getUserByUserName(String userName) {
 6         String hql="from User where userName=?";
 7         Session session=HibernateUtil.getSession();
 8         Transaction tx=session.beginTransaction();
 9         Query query=session.createQuery(hql);
10         query.setString(0,userName);
11         List<User> user=query.list();
12         tx.commit();
13                 //===区别===
14         if(user.size()==0)
15             return null;
16         return user.get(0);
17     }