JavaWeb servlet 使用Cookie记录用户访问次数

创建cookieLoginTime继承HttpServlet

重写doGet,doPost方法就不再赘述,我们的侧重点是在使用cookie记录信息
cookie是由一个个的键值对组成,就类似哈希,或者数组(一个下标对一个数据)
cookie无法直接搜索到name就直接删除,操作cookie只是添加和修改倒是问题不大

我先简单写一下doget和dopost

然后去web.xml里定义映射

然后开始写doget的细节

几个问题:1乱码,2cookie的value增加
乱码在前面加

resp.setHeader("Content-Type", "text/html;charset=UTF-8");
req.setCharacterEncoding("UTF-8");

若果不设置cookie的path,则名字相同的cookie视为相同的cookie,后面的覆盖前面的,注意：大小写敏感
参考:https://blog.csdn.net/czh500/article/details/80420061

所以我们可以用这个特点获取然后添加cookie

package top.sehnsucht;

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;



public class cookieLoginTime extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setHeader("Content-Type", "text/html;charset=UTF-8");
        req.setCharacterEncoding("UTF-8");
        cookie[] cookies = req.getcookies();

        for (cookie cookie : cookies) {
            if ("time".equals(cookie.getName())) {
                int time = Integer.parseInt(cookie.getValue()) + 1;
                resp.getWriter().println("这是您第" + time + "次访问本站");
                resp.addcookie(new cookie(cookie.getName(), Integer.toString(time)));
                return;
            }
        }
        cookie cookie = new cookie("time", "1");
        resp.getWriter().println("这是您第" + cookie.getValue() + "次访问本站");
        resp.addcookie(cookie);
    }

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

  Archetype Created Web Application
  
    hello
    top.sehnsucht.HelloServlet
  
  
    hello
    /hello
  

  
    loginTime
    top.sehnsucht.cookieLoginTime
  
  
    loginTime
    /time