J2EE知识点3 - JS操作Cookie 应用 - 《Java笔记》

<script type="text/javascript">
    window.onload = function(){
      var cookieObject = document.cookie;--%>
    <%--//  String类型的   k1=v1;k2=v2--%>
      alert(cookieObject);
      var cookieMessage = cookieObject.split(";");//[k1=v1,k2=v2]
      for(var i=0;i<cookieMessage.length;i++){
          var kv = cookieMessage[i].split("=");//[k1,v1]  [k2,v2]
          alert(kv[0]+"---"+kv[1]);
      }
  }
</script>

模拟七天免登陆

package controller;

import service.LoginService;

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 java.io.IOException;

public class LoginController extends HttpServlet {
    @Override
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String username=req.getParameter("username");
        String password=req.getParameter("password");
        //如果参数没有接收到，去cookie找
        if(username==null&&password==null){
            Cookie[] cookies=req.getCookies();
            for(Cookie cookie:cookies){
                if(cookie.getName().equals("username")){
                    username=cookie.getValue();
                }
                if(cookie.getName().equals("password")){
                    password=cookie.getValue();
                }
            }
        }

        LoginService service=new LoginService();
        String result=service.login(username,password);
        if(result.equals("登录成功")){
            //如果用户勾选了七日自动登录，需要将账号密码存入cookie
            String[] values= req.getParameterValues("flag");
            if(values!=null&&values.length>=0){
                Cookie nameCookie=new Cookie("username",username);
                Cookie passwordCookie=new Cookie("password",password);
                nameCookie.setMaxAge(10);
                passwordCookie.setMaxAge(10);
                resp.addCookie(nameCookie);
                resp.addCookie(passwordCookie);
            }
            req.getRequestDispatcher("welcome.jsp").forward(req,resp);
        }else{
            req.getRequestDispatcher("index.jsp").forward(req,resp);
        }
    }
}

package service;

public class LoginService {
    public String login(String username,String password){
        if(username.equals("klxh")&&password.equals("554599")){
            return "登录成功";
        }
        return "账号或密码错误";
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">

    <servlet>
        <servlet-name>login</servlet-name>
        <servlet-class>controller.LoginController</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>login</servlet-name>
        <url-pattern>/login</url-pattern>
    </servlet-mapping>

</web-app>

index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <%
    Cookie[] cookies = request.getCookies();
    if(cookies!=null && cookies.length>1){
      request.getRequestDispatcher("login").forward(request,response);
    }
  %>
  <body>
    <form action="login" method="post">
      账号:<input type="text" name="username" value=""><br>
      密码:<input type="password" name="password" value=""><br>
      <input type="checkbox" name="flag" value="true">7天内自动登陆<br>
      <input type="submit" value="登录"><br>
    </form>
  </body>
</html>

welcome.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
    <head>

    </head>
    <body>
        ${cookie.username.value}
        我是welcome资源信息
    </body>
</html>