【Javaweb】实现Cookie关于当前时间显示的Demo

实现COOKIE关于当前时间显示的Demo

使用Servlet实现。

java代码：

import javax.servlet.ServletException;
import javax.servlet.http.COOKIE;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Date;
public class COOKIEDemo01 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//解决乱码问题
req.setCharacterEncoding("utf-16");
resp.setCharacterEncoding("utf-16");
PrintWriter out = resp.getWriter();
//COOKIE，服务器从客户端获取
COOKIE[] COOKIEs = req.getCOOKIEs(); //返回数组，说明COOKIE存在多个
if(COOKIEs!=null){
out.write("你上一次访问的时间是：");
for (int i = 0; i < COOKIEs.length; i++) {
COOKIE COOKIE = COOKIEs[i];
if(COOKIE.getName().equals("lastLoginTime")) {
//获取COOKIE中的值
long lastLoginTime = Long.parseLong(COOKIE.getValue());
Date date = new Date(lastLoginTime);
out.write(date.toLocaleString());
}
}
}else {
out.write("这是您第一次访问本站");
}
//服务给客户端响应一个COOKIE
COOKIE COOKIE = new COOKIE("lastLoginTime", System.currentTimeMillis() + "");// 通过+""将输出的当前时间转化为字符串
resp.addCOOKIE(COOKIE);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req, resp);
}
}


对相关的Servlet进行注册

web.xml内容：


<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
version="4.0"
metadata-complete="true">
<servlet>
<servlet-name>COOKIEDemo01servlet-name>
<servlet-class>com.donric.servlet.COOKIEDemo01servlet-class>
servlet>
<servlet-mapping>
<servlet-name>COOKIEDemo01servlet-name>
<url-pattern>/COOKIEurl-pattern>
servlet-mapping>
web-app>


最后配置一下tomcat就好了。