JavaWeb（二）cookie与session的应用

前言

　　前面讲了一堆虚的东西，所以这篇我们来介绍一下cookie和session的应用。

1.1、思路介绍

　　

1.2、实现代码

　　1）LoginServlet

package com.zyh.cookie;

import java.io.IOException;
import java.io.PrintWriter;

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 LoginServlet extends HttpServlet {

    public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        PrintWriter out = response.getWriter();
        String userName = "";
        String checked = "";
        
        //得到客户端保存的cookie数据
        Cookie[] cookies = request.getCookies();
        //因为第一次的时候没有cookie，所以不谢cookies!=null的话，空指针异常的。
        for (int i = 0; cookies!=null&&i < cookies.length; i++) {
            if("userName".equals(cookies[i].getName())){
                 userName = cookies[i].getValue();
                 checked = "checked='checked'";
            }
        }
        
        out.print("<form action='"+request.getContextPath()+"/doLoginServlet' type='post'>");
        out.print("用户名:<input type='text' name='userName' value='"+userName+"' /><br/>");
        out.print("密码:<input type='password' name='pwd' /><br/>");
        out.print("记住用户名:<input type='checkbox' name='remember' "+checked+" /><br/>");
        out.print("<input type='submit' value='提交' /><br/>");
        out.print("</form>");
        
    }


    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        
    }

}

LoginServlet