public class UserAction extends ActionSupport{
     
    private String userid;
    private String password;
    private User user;
    private List<User> listUser;
     
    public String showuser() throws Exception{
        this.setUserid(getUserid());
        User userShow = UserDAO.getUser(userid);
         
        return SUCCESS;
    }
     
    public String login () throws Exception{
        this.setUserid(getUserid());
        this.setPassword(getPassword());
         
        if (this.getUserid()==null||this.getUserid().length()==0){
            System.out.println ("请输入userid!");
            return ERROR;
            }
        else{
                List listUserRw = UserDAO.checkUser(userid, password);
                if(listUserRw.size()>0){
                    System.out.println("账号密码正确，登陆成功！");
                    return SUCCESS;
                }
                else{
                    System.out.println("账号或密码错误！");
                    return ERROR;
                    }
                 
        }
         
         
    }
    //省略get set方法
}   

public static List<User> checkUser(String userId,String userPwd) {
        Transaction tx = null;
        List<User> list = null;
        try {
            Session session = HibernateSessionFactory.getSessionFactory()
                    .openSession();
            tx = session.beginTransaction();
            Query query = session.createQuery("from User as u where u.userId=:userId and u.userPwd=:userPwd");
            query.setString("userId", userId);    
            query.setString("userPwd", userPwd);
            list = query.list();                            
            tx.commit();}
        catch (Exception e) {
            e.printStackTrace();
            tx.rollback();
        }
        HibernateSessionFactory.closeSession();
        return list;
    }

<form action="login.action" method="post">
　　<input type="text" name="userid" class="username" placeholder="请输入您的用户名！">
　　<input type="password" name="password" class="password" placeholder="请输入您的用户密码！">
       
　　<button type="submit" class="submit_button">登录</button>
　　<div class="error"><span>+</span></div>
</form>