Cookie 的有效路径访问权限，及测试；Cookie的删除演示

声明使用的JDK9&Tomcat9版本；

① cookie的有效路径仅仅能被其自身和其子路径访问；

② 当cookie的有效路径为 / 时候，web项目下所有的路径均可以访问到 cookie；

测试如下：

创建cookie：

访问 servlet 以生成 cookie path ；

查看 localhost cookie path ，name为 ：path ，内容为 ：设置了cookie的 path；

cookie的有效路径 /web/a/b/c ,用 servlet2 的路径访问获取 cookie：

更换 servlet 3的路径访问获取cookie ,访问不到 cookie：

访问结果如下：

当有效路径 path 为 / 时候：

然后进行访问 ;

可以访问到 ;

path1 中设置了cookie的 path，path2和path3分别为path的子路径和父路径；代码如下：

path1 ；

package com.baidu.Servlet;
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;
@WebServlet(name = "Path3", urlPatterns = "/web/a")
public class Path3 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);//
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //乱码问题
        //获取cookie  然后打印name&value
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        Cookie[] cookies = request.getCookies();
        for (Cookie cookie : cookies) {
            System.out.println(cookie.getName());
            System.out.println(cookie.getValue());
        }
    }
}

path2 ；

package com.baidu.Servlet;
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;
@WebServlet(name = "Path2", urlPatterns = "/web/a/b/c/d")
public class Path2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);//
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //防止乱码
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        //获取cookie
        Cookie[] cookies = request.getCookies();
        for (Cookie cookie : cookies) {   //打印  cookie 的name&value
            String value = cookie.getValue();
            System.out.println(cookie.getName());
            System.out.println(value);
        }
    }
//    void  setPath(String path)
}

path3

package com.baidu.Servlet;
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;
@WebServlet(name = "Path3", urlPatterns = "/web/a")
public class Path3 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);//
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //乱码问题
        //获取cookie  然后打印name&value
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        Cookie[] cookies = request.getCookies();
        for (Cookie cookie : cookies) {
            System.out.println(cookie.getName());
            System.out.println(cookie.getValue());
        }
    }
}

然后就可点击启动Tomcat,访问path1服务器进行测试；

cookie 的删除原理：

使用创建同名的 cookie 【name相同，value =“ ” 】

并且把 cookie的存活时间设置为0 ；新创建的 cookie的有效路径，必须要和要删除的 cookie的有效路径保持一致；

这样浏览器会自动替换新的 cookie；

浏览器中存在name=path 的cookie【就是上面的path1 创建的cookie，现在要删除它】

创建删除cookie的servlet，并在浏览器中访问该servlet；

查看cookie已经被删除【名字为path的cookie 在localhost 目录下，查看已经不存在该cookie】；

新创建的 cookie 代码如下，要删除的参考上面 path1：

package com.baidu.Servlet;
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;
@WebServlet(name = "DeleteCookie", urlPatterns = "/del")
public class DeleteCookie extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);//
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        response.setContentType("text/html;charset=utf-8");
        //利用cookie 的同名覆盖delete cookie
        Cookie cookie = new Cookie("path","");
        cookie.setMaxAge(0);
        cookie.setPath("/web/a/b/c");//要保证有效路径一致
        response.addCookie(cookie);
        response.getWriter().print("删除成功");
    }
}

Cookie 的有效路径访问权限，及测试；Cookie的删除演示

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