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Cookie就是服务器保存在客户端的数据,Cookie是由服务器创建,
package com.sheng.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;
//显示上一次访问的时间
//Cookie就是服务器保存在客户端的数据,Cookie是由服务器创建,
public class Damo4Cookie extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置服务器端以utf-8编码进行输出
response.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
// 第一步.获得从客户端带过来的所有的Cookie:
Cookie[] cookies=request.getCookies();
PrintWriter out=response.getWriter();
//如果用户是第一次访问,那么得到cookies将是null
//第二步.从所有的Cookie中查找指定名称的Cookie:
if (cookies!=null) {
out.write("您上次访问的时间是:");
for (int i = 0; i < cookies.length; i++) {
Cookie cookie=cookies[i];
if (cookie.getName().equals("lastAccessTime")) {
//第四步.记录当前的时间,并且利用Cookie将时间回写到浏览器端.
Long lastAccesTime=Long.parseLong(cookie.getValue());
Date data=new Date(lastAccesTime);
out.write(data.toLocaleString());
System.out.println(cookies[0]);
}
}
}else {
out.write("这时您第一次访问本站");
}
Cookie cookie=new Cookie("lastAccessTime", System.currentTimeMillis()+"");
//将cookie对象添加到response对象中,这样,服务器在输出response对象内容就会将cookie对象给输出出去
response.addCookie(cookie);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}