JAVA-EE使用Cookie向本地的硬盘保存信息解决无状态------计算机网络经典

女爷i 2024-02-21 09:52 40阅读 0赞

>     <%@ page contentType="text/html;charset=UTF-8" language="java" %>
>     <%--访问JSP不允许生成Session对象--%>
>     <%@ page session="false" %>
>     <!DOCTYPE html>
>     <html>
>     <head>
>         <meta charset="utf-8">
>         <title>欢迎页</title>
>     </head>
>     <body>
>         <h1>用户登录</h1>
>         <hr>
>         <form action="<%=request.getContextPath()%>/user/login" method="post">
>             username:<input type="text" name="username"><br>
>             password:<input type="password" name="password"><br>
>             <input type="submit" value="login">
>         </form>
>         <h1>
>             <a href="<%=request.getContextPath()%>/cookie/generate">
>                 服务器生成Cookie,然后把Cookie传给浏览器,浏览器收到,再放到客户端上
>             </a>
>         </h1>
>         <h1>
>             <a href="<%=request.getContextPath()%>/sendCookie">
>                 浏览器发送Cookie给服务器
>             </a>
>         </h1>
>     <%--    前端发送请求路径的时候,如果请求路径是绝对路径,要以/开始,加项目名--%>
>     <%--    <h1><a href="<%=(request.getContextPath())%>/dept/list">查看部门列表</a></h1>--%>
>     </body>
>     </html>
> 
>     <%@ page contentType="text/html;charset=UTF-8" language="java" %>
>     <%--访问JSP不允许生成Session对象--%>
>     <%@ page session="false" %>
>     <!DOCTYPE html>
>     <html>
>     <head>
>         <meta charset="utf-8">
>         <title>欢迎页</title>
>     </head>
>     <body>
>         <h1>用户登录</h1>
>         <hr>
>         <form action="<%=request.getContextPath()%>/user/login" method="post">
>             username:<input type="text" name="username"><br>
>             password:<input type="password" name="password"><br>
>             <input type="submit" value="login">
>         </form>
>         <h1>
>             <a href="<%=request.getContextPath()%>/cookie/generate">
>                 服务器生成Cookie,然后把Cookie传给浏览器,浏览器收到,再放到客户端上
>             </a>
>         </h1>
>         <h1>
>             <a href="<%=request.getContextPath()%>/sendCookie">
>                 浏览器发送Cookie给服务器
>             </a>
>         </h1>
>     <%--    前端发送请求路径的时候,如果请求路径是绝对路径,要以/开始,加项目名--%>
>     <%--    <h1><a href="<%=(request.getContextPath())%>/dept/list">查看部门列表</a></h1>--%>
>     </body>
>     </html>

>     package com.bjpowernode.oa.web.action;
>     
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.annotation.WebServlet;
>     import jakarta.servlet.http.Cookie;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>     
>     import java.io.IOException;
>     @WebServlet("/cookie/generate")
>     public class GenerateCookie extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
>         {
>             //创建Cookie
>             Cookie cookie = new Cookie("username","zhangsan");
>     //        cookie.setMaxAge(60 * 60);
>             //设置cookie生命为一小时,只要这里有时间就会保存到硬盘中
>     //        cookie.setMaxAge(0);
>             //没有设置有效时间默认保存在浏览器运行内存中,断电自动消失
>             //设置有效期为0最主要的作用在于删除浏览器上的同名cookie
>             cookie.setMaxAge(-1);
>             //设置Cookie的有效期小于0,表示cookie不会被删除
>             //如果设置的时间小于0,和不调用maxAGE的效果一样,都是不把cookie保存到硬盘内
>             //没有设置Cookie的情况下,cookie自动关联的就是她自己,她的上级和她的上级的子路径才有cookie
>             cookie.setPath(request.getContextPath());
>             response.addCookie(cookie);
>         }
>     }
> 
>     package com.bjpowernode.oa.web.action;
>     
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.annotation.WebServlet;
>     import jakarta.servlet.http.Cookie;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>     
>     import java.io.IOException;
>     @WebServlet("/cookie/generate")
>     public class GenerateCookie extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
>         {
>             //创建Cookie
>             Cookie cookie = new Cookie("username","zhangsan");
>     //        cookie.setMaxAge(60 * 60);
>             //设置cookie生命为一小时,只要这里有时间就会保存到硬盘中
>     //        cookie.setMaxAge(0);
>             //没有设置有效时间默认保存在浏览器运行内存中,断电自动消失
>             //设置有效期为0最主要的作用在于删除浏览器上的同名cookie
>             cookie.setMaxAge(-1);
>             //设置Cookie的有效期小于0,表示cookie不会被删除
>             //如果设置的时间小于0,和不调用maxAGE的效果一样,都是不把cookie保存到硬盘内
>             //没有设置Cookie的情况下,cookie自动关联的就是她自己,她的上级和她的上级的子路径才有cookie
>             cookie.setPath(request.getContextPath());
>             response.addCookie(cookie);
>         }
>     }

>     package com.bjpowernode.oa.web.action;
>     
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.annotation.WebServlet;
>     import jakarta.servlet.http.Cookie;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>     
>     import java.io.IOException;
>     import java.io.PrintWriter;
>     
>     @WebServlet("/sendCookie")
>     public class Receiver extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
>         {
>             response.setContentType("text/html;charset=UTF-8");
>             Cookie[] cookies = request.getCookies();
>             PrintWriter out = response.getWriter();
>             if (cookies != null)
>             {
>                 for (int i = 0; i < cookies.length; i++)
>                 {
>                     String name = cookies[i].getName();
>                     String value = cookies[i].getValue();
>                     out.println(name + value);
>                 }
>             }
>         }
>     }
> 
>     package com.bjpowernode.oa.web.action;
>     
>     import jakarta.servlet.ServletException;
>     import jakarta.servlet.annotation.WebServlet;
>     import jakarta.servlet.http.Cookie;
>     import jakarta.servlet.http.HttpServlet;
>     import jakarta.servlet.http.HttpServletRequest;
>     import jakarta.servlet.http.HttpServletResponse;
>     
>     import java.io.IOException;
>     import java.io.PrintWriter;
>     
>     @WebServlet("/sendCookie")
>     public class Receiver extends HttpServlet
>     {
>         @Override
>         protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException
>         {
>             response.setContentType("text/html;charset=UTF-8");
>             Cookie[] cookies = request.getCookies();
>             PrintWriter out = response.getWriter();
>             if (cookies != null)
>             {
>                 for (int i = 0; i < cookies.length; i++)
>                 {
>                     String name = cookies[i].getName();
>                     String value = cookies[i].getValue();
>                     out.println(name + value);
>                 }
>             }
>         }
>     }