(1)如何创建cookie案例
- package com.tsinghua;
- import javax.servlet.http.*;
- import java.io.*;
- public class CookieTest1 extends HttpServlet{
- //处理get请求
- public void doGet(HttpServletRequest req,HttpServletResponse res){
- try {
- res.setContentType("text/html;charset=gbk");
- PrintWriter pw=res.getWriter();
- //当用户访问该servlet时, 就将信息创建到该用户的cookie中
- //1. 现在服务器端创建一个cookie
- Cookie myCookie=new Cookie("color1","red");
- //2. 该cookie存在的时间 以秒为单位
- myCookie.setMaxAge(30000);
- //如果你不设置存在时间,那么该cookie将不会保存
- //3. 将该cookie写回到客户端
- res.addCookie(myCookie);
- pw.println("已经创建了cookie");
- }
- catch (Exception ex) {
- ex.printStackTrace();
- }
- }
- }
(2)如何读取cookie案例
- package com.tsinghua;
- import javax.servlet.http.*;
- import java.io.*;
- public class CookieTest2 extends HttpServlet{
- //处理get请求
- public void doGet(HttpServletRequest req,HttpServletResponse res){
- try {
- res.setContentType("text/html;charset=gbk");
- PrintWriter pw=res.getWriter();
- //从客户端得到所有cookie信息
- Cookie [] allCookies=req.getCookies();
- int i=0;
- //如果allCookies不为空...
- if(allCookies!=null){
- //从中取出cookie
- for(i=0;i<allCookies.length;i++){
- //依次取出
- Cookie temp=allCookies[i];
- if(temp.getName().equals("color1")){
- //得到cookie的值
- String val=temp.getValue();
- pw.println ("color1="+val);
- break;
- }
- }
- if(allCookies.length==i){
- pw.println("cookie 过期");
- }
- }else{
- pw.println ("不存在color1这个cookie/或是过期了!");
- }
- }
- catch (Exception ex) {
- ex.printStackTrace();
- }
- }
- }
(3)如何删除cookie案例
- package com.tsinghua;
- import javax.servlet.http.*;
- import java.io.*;
- public class CookieTest3 extends HttpServlet{
- //处理get请求
- public void doGet(HttpServletRequest req,HttpServletResponse res){
- try {
- res.setContentType("text/html;charset=gbk");
- PrintWriter pw=res.getWriter();
- //从客户端得到所有cookie信息
- Cookie [] allCookies=req.getCookies();
- int i=0;
- //如果allCookies不为空...
- if(allCookies!=null){
- //从中取出cookie
- for(i=0;i<allCookies.length;i++){
- //依次取出
- Cookie temp=allCookies[i];
- if(temp.getName().equals("color")){
- //将该cookie删除
- temp.setMaxAge(0);
- pw.println("删除了color这个cookie");
- break;
- }
- }
- }
- }
- catch (Exception ex) {
- ex.printStackTrace();
- }
- }
- }