当用户访问网站时，可以获取到上次访问的时间
package cookie;
import java.io.IOException;
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;
/*
* 在网页中显示上次访问时间
*/
public class CookieDemo1 extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
//1.获取本次访问时间
String dateStr1 = new Date().toString();
//2.将本次访问时间通过cookie发送给浏览器保存
response.setHeader("Set-Cookie", dateStr1);
//>>创建Cookie对象
Cookie cookie=new Cookie("time", dateStr1);
//>>设置cookie的最大存活时间(单位是秒)
cookie.setMaxAge(3600*24);
//>>设置cookie的path为当前web应用的虚拟路径
cookie.setPath(request.getContextPath()+"/");
//>>将cookie添加到response中，发送给浏览器保存
response.addCookie(cookie);
//3.获取上一次访问的时间
//>>获取请求中的所有cookie(对象组成的数组)
Cookie[]cs=request.getCookies();
//>>遍历所有cookie找出名称为time的cookie,获取上次访问时间
String dateStr2=null;
if(cs!=null)
{
for (Cookie c : cs) {
if("time".equals(c.getName()))
{
dateStr2=c.getValue();
}
}
}
if(dateStr2!=null)
{
//4.将上次访问时间发送给浏览器并显示在网页中
response.getWriter().write("您上次访问时间为:"+dateStr2);
}else{
//5.没有上次访问时间,则响应第一次访问
response.getWriter().write("您是第一次访问本网站");
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
package cookie;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/*
* 删除cookie
*/
public class CookieRemoved extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//删除名称为time，path为当前web应用虚拟路径的cookie
//1.创建一个名称为time的cookie
Cookie cookie=new Cookie("time","");
//2.设置cookie的path为当前web应用的虚拟路径
cookie.setPath(request.getContextPath()+"/");
//3.设置cookie的存活时间为0
cookie.setMaxAge(0);
//4.将cookie发送给浏览器
response.addCookie(cookie);
response.getWriter().write("Cookie delete Success");
}
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
运行结果:
您是第一次访问本网站
第一次访问
您上次访问时间为:Tue Aug 21 00:04:16 CST 2018
第二次访问
您上次访问时间为:Tue Aug 21 00:07:13 CST 2018
第三次访问
Cookie delete Success
删除cookie
您是第一次访问本网站
再次访问
您上次访问时间为:Tue Aug 21 00:18:23 CST 2018
再次访问
