cookie与session学习笔记 -- day03 cookie的使用

一、使用cookie记录最后访问时间的练习

1.创建web项目，编写servlet

package com.cookie;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class CookieServlet extends HttpServlet{

protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
//获取客户端传递的cookies
Cookie[] cookies = request.getCookies();
if(null != cookies && cookies.length > 0){
for (Cookie cookie : cookies) {
if("lastAccessTime".equals(cookie.getName())){
out.write("您最后的访问时间为：" + new Date(Long.parseLong(cookie.getValue())).toLocaleString());
}
}
}

//向客户端保存cookie数据
Cookie cookie = new Cookie("lastAccessTime", System.currentTimeMillis()+"");
response.addCookie(cookie);//将cookie写回到浏览器
}

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
this.doPost(req, resp);
}
}

2.配置web.xml中的 servlet 映射

<servlet>
<servlet-name>cookieServlet</servlet-name>
<servlet-class>com.cookie.CookieServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>cookieServlet</servlet-name>
<url-pattern>/servlet/ck1</url-pattern>
</servlet-mapping>

3.启动项目，使用浏览器访问，查看效果