cookie实现自动登陆(1)

完整的代码，用途请参见注释 

CookieUtil.java

处理cookie的工具类,包括读取,保存,清除三个主要方法。

      

package cn.itcast.util;

import java.io.IOException;

import java.io.PrintWriter;

import java.io.UnsupportedEncodingException;

import javax.servlet.FilterChain;

import javax.servlet.ServletException;

import javax.servlet.http.Cookie;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import javax.servlet.http.HttpSession;

import java.security.MessageDigest;

import java.security.NoSuchAlgorithmException;

import cn.itcast.bean.User;

import cn.itcast.dao.UserDAO;

import cn.itcast.factory.DaoImplFactory;

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64; 

public class CookieUtil {

       //保存cookie时的cookieName

       private final static String cookieDomainName = “cn.itcast”;

      

       //加密cookie时的网站自定码

       private final static String webKey = “itcast”;

      

//设置cookie有效期是两个星期，根据需要自定义

       private final static long cookieMaxAge = 60 * 60 * 24 * 7 * 2;        

       public static void saveCookie(User user, HttpServletResponse response) {

             

              //cookie的有效期

              long validTime = System.currentTimeMillis() + (cookieMaxAge * 1000);

             

              //MD5加密用户详细信息

              String cookieValueWithMd5 =getMD5(user.getUserName() + ":" + user.getPassword()

                            + ":" + validTime + ":" + webKey);

             

              //将要被保存的完整的Cookie值

              String cookieValue = user.getUserName() + ":" + validTime + ":" + cookieValueWithMd5;

             

              //再一次对Cookie的值进行BASE64编码

              String cookieValueBase64 = new String(Base64.encode(cookieValue.getBytes()));

             

              //开始保存Cookie

              Cookie cookie = new Cookie(cookieDomainName, cookieValueBase64);
           

cookie.setMaxAge(60 * 60 * 24 * 365 * 2);

//cookie有效路径是网站根目录

              cookie.setPath("/");

              //向客户端写入

              response.addCookie(cookie);

       }