web实现登录注册功能视频

package com.imooc.servlet;

import java.io.IOException;

import java.util.List;

import javax.servlet.ServletException;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import com.imooc.domain.User;

/**

 *用户登录的Servlet

 */

public class LoginServlet extends HttpServlet {

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

//接收数据

request.setCharacterEncoding("UTF-8");

response.setCharacterEncoding("UTF-8");

String username = request.getParameter("username");

String password = request.getParameter("password");

//校验用户是否正确

List<User> users = (List<User>) this.getServletContext().getAttribute("list");

for (User user : users) {

if(user.getName().equals(username)){

//用户名正确

if(user.getPassword().equals(password)){

//密码正确

//登录成功

//判断复选框是否勾选

String remember = request.getParameter("remember");

if("true".equals(remember)){

//完成记住用户名功能

Cookie cookie = new Cookie("username", user.getName());

//设置路径和有效时间

cookie.setPath("/reg_login_mvc");

//设置有效时间

cookie.setMaxAge(60*60*24);//保存24小时

//将cookie写回浏览器

response.addCookie(cookie);

}

//将用农户信息保存到session中

request.getSession().setAttribute("user", user);

response.sendRedirect(request.getContextPath()+"/success.jsp");

return;

}

else {

request.setAttribute("err", "密码错误");

request.getRequestDispatcher("/login.jsp").forward(request, response);

}

}else {

request.setAttribute("msg", "用户名不存在");

request.getRequestDispatcher("/login.jsp").forward(request, response);

}

}

}

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

// TODO Auto-generated method stub

doGet(request, response);

}

}

老师，发了

老师，我在第二次注册，然后登录新注册的账号时出现错误如下：

登录代码如下：

在网上百度了一下，说是在提交之前我改变了response，可是看了一下，好像没有呀，老师，您看看这是为啥吧