java web实现自动登录

//存储 session

   request.getSession().setAttribute( "userBean" , queryUser);

  Cookie cookie = new Cookie( "auto_login" , username + "#" + password);

// 创建 cookie

     cookie.setMaxAge( 60 * 60 * 24 * 7 );  //设置时间为 一周

     cookie.setPath(request.getContextPath());

     response.addCookie(cookie);

package com.wl.servlet;

import com.wl.dao.UserDao;

import com.wl.dao.daoImpl.UserDaoImpl;

import com.wl.domain.UserBean;

import javax.servlet.ServletException;

import javax.servlet.annotation.WebServlet;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.io.IOException;

import java.sql.SQLException;

@WebServlet (name = "LoginServlet" )

public class LoginServlet extends HttpServlet {

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

         this .doGet(request, response);

     }

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

         try {

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

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

             String autoLogin = request.getParameter( "auto_login" );

             System.out.println(username + " = " + password + "  " + autoLogin);

             UserBean userBean = new UserBean();

             userBean.setPassword(password);

             userBean.setUsername(username);

             UserDao userDao = new UserDaoImpl();

             UserBean queryUser = userDao.login(userBean);

             if (queryUser != null ){

                 if ( "on" .equals(autoLogin)){

                     Cookie cookie = new Cookie( "auto_login" , username + "#" + password);

                     cookie.setMaxAge( 60 * 60 * 24 * 7 );

                     cookie.setPath(request.getContextPath());

                     response.addCookie(cookie);

                 }

                 request.getSession().setAttribute( "userBean" , queryUser);

                 response.sendRedirect( "index.jsp" );

             } else {

                 request.getSession().setAttribute( "errorInfo" , "用户名密码不正确" );

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

             }

         } catch (SQLException e) {

             e.printStackTrace();

         }

     }

}

package com.wl.filter;

import com.wl.dao.UserDao;

import com.wl.dao.daoImpl.UserDaoImpl;

import com.wl.domain.UserBean;

import util.CookieUtil;

import javax.servlet.*;

import javax.servlet.annotation.WebFilter;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServletRequest;

import java.io.IOException;

import java.sql.SQLException;

@WebFilter (filterName = "AutoLoginFilter" )

public class AutoLoginFilter implements Filter {

     public void destroy() {

     }

     public void doFilter(ServletRequest req, ServletResponse resp, FilterChain chain) throws ServletException, IOException {

         HttpServletRequest request = (HttpServletRequest) req;

         UserBean userBean = (UserBean) request.getSession().getAttribute( "userBean" );

         if (userBean != null ){

             chain.doFilter(req, resp);

         } else {

             Cookie[] cookies = request.getCookies();

             Cookie auto_login = CookieUtil.findCookie(cookies, "auto_login" );

             if (auto_login == null ) {

                 chain.doFilter(req,resp);

             } else {

                 String value = auto_login.getValue();

                 String username = value.split( "#" )[ 0 ];

                 String password = value.split( "#" )[ 1 ];

                 UserBean user = new UserBean();

                 user.setUsername(username);

                 user.setPassword(password);

                 UserDao dao = new UserDaoImpl();

                 try {

                     UserBean login = dao.login(user);

                     request.getSession().setAttribute( "userBean" , login);

                 } catch (SQLException e) {

                     e.printStackTrace();

                 }

                 chain.doFilter(req, resp);

             }

         }

         chain.doFilter(req, resp);

     }

     public void init(FilterConfig config) throws ServletException {

     }

}