Cookie实现记住用户名、密码
今天做一个项目就是有一个记住用户名的，选中复选框则记住用户名和密码，下次登录的时候就方便用户名的登陆：package com.laizhi.util;002
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import java.io.IOException;
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import java.io.PrintWriter;
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import java.io.UnsupportedEncodingException;
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import javax.servlet.FilterChain;
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import javax.servlet.ServletException;
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import javax.servlet.http.Cookie;
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import javax.servlet.http.HttpServletRequest;
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import javax.servlet.http.HttpServletResponse;
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import javax.servlet.http.HttpSession;
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import java.security.MessageDigest;
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import java.security.NoSuchAlgorithmException;
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import com.laizhi.bean.User;
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import com.laizhi.dao.UserDAO;
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import com.laizhi.factory.DaoImplFactory;
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import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
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/*
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* 2014.07.01
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* */
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public class CookieUtil {
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//保存cookie时的cookieName
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private final static String cookieDomainName = “laizhi”;
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//加密cookie时的网站自定码
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private final static String webKey = “123456”;
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//设置cookie有效期是两个星期，根据需要自定义
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private final static long cookieMaxAge = 60 * 60 * 24 * 7 * 2;
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//保存Cookie到客户端-------------------------------------------------------------------------
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//在CheckLogonServlet.java中被调用
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//传递进来的user对象中封装了在登陆时填写的用户名与密码
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public static void saveCookie(User user, HttpServletResponse response) {
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//cookie的有效期
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long validTime = System.currentTimeMillis() + (cookieMaxAge * 5000);
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//MD5加密用户详细信息
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String cookieValueWithMd5 =getMD5(user.getUserName() + ":" + user.getPassword()
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+ ":" + validTime + ":" + webKey);
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//将要被保存的完整的Cookie值
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String cookieValue = user.getUserName() + ":" + validTime + ":" + cookieValueWithMd5;
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//再一次对Cookie的值进行BASE64编码
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String cookieValueBase64 = new String(Base64.encode(cookieValue.getBytes()));
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//开始保存Cookie
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Cookie cookie = new Cookie(cookieDomainName, cookieValueBase64);
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//存两年(这个值应该大于或等于validTime)
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cookie.setMaxAge(60 * 60 * 24 * 365 * 2);
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//cookie有效路径是网站根目录
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cookie.setPath("/");
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//向客户端写入
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response.addCookie(cookie);
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}
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//读取Cookie,自动完成登陆操作----------------------------------------------------------------
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//在Filter程序中调用该方法,见AutoLogonFilter.java
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public static void readCookieAndLogon(HttpServletRequest request, HttpServletResponse response,
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FilterChain chain) throws IOException, ServletException,UnsupportedEncodingException{
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//根据cookieName取cookieValue
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Cookie cookies[] = request.getCookies();
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String cookieValue = null;
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if(cookies!=null){
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for(int i=0;i
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if (cookieDomainName.equals(cookies.getName())) {
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cookieValue = cookies.getValue();
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break;
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}
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}
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}
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//如果cookieValue为空,返回,
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if(cookieValue==null){
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return;
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}
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//如果cookieValue不为空,才执行下面的代码
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//先得到的CookieValue进行Base64解码
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String cookieValueAfterDecode = new String (Base64.decode(cookieValue),"utf-8");
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//对解码后的值进行分拆,得到一个数组,如果数组长度不为3,就是非法登陆
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String cookieValues[] = cookieValueAfterDecode.split(":");
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if(cookieValues.length!=3){
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response.setContentType("text/html;charset=utf-8");
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PrintWriter out = response.getWriter();
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out.println("你正在用非正常方式进入本站...");
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out.close();
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return;
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}
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//判断是否在有效期内,过期就删除Cookie
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long validTimeInCookie = new Long(cookieValues);
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if(validTimeInCookie < System.currentTimeMillis()){
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//删除Cookie
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clearCookie(response);
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response.setContentType("text/html;charset=utf-8");
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PrintWriter out = response.getWriter();
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out.println("");你的Cookie已经失效,请重新登陆
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out.close();
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return;
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}
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//取出cookie中的用户名,并到数据库中检查这个用户名,
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String username = cookieValues;
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//根据用户名到数据库中检查用户是否存在
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UserDAO ud = DaoImplFactory.getInstance();
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User user = ud.selectUserByUsername(username);
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//如果user返回不为空,就取出密码,使用用户名+密码+有效时间+ webSiteKey进行MD5加密
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if(user!=null){
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String md5ValueInCookie = cookieValues;
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String md5ValueFromUser =getMD5(user.getUserName() + ":" + user.getPassword()
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+ ":" + validTimeInCookie + ":" + webKey);
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//将结果与Cookie中的MD5码相比较,如果相同,写入Session,自动登陆成功,并继续用户请求
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if(md5ValueFromUser.equals(md5ValueInCookie)){
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HttpSession session = request.getSession(true);
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session.setAttribute("user", user);
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chain.doFilter(request, response);
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}
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}else{
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//返回为空执行
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response.setContentType("text/html;charset=utf-8");
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PrintWriter out = response.getWriter();
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out.println("cookie验证错误！");
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out.close();
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return;
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}
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}
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//用户注销时,清除Cookie,在需要时可随时调用-----------------------------------------------------
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public static void clearCookie( HttpServletResponse response){
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Cookie cookie = new Cookie(cookieDomainName, null);
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cookie.setMaxAge(0);
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cookie.setPath("/");
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response.addCookie(cookie);
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}
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//获取Cookie组合字符串的MD5码的字符串----------------------------------------------------------------
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public static String getMD5(String value) {
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String result = null;
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try{
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byte[] valueByte = value.getBytes();
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MessageDigest md = MessageDigest.getInstance("MD5");
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md.update(valueByte);
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result = toHex(md.digest());
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} catch (NoSuchAlgorithmException e2){
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e1.printStackTrace();
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}
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return result;
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}
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//将传递进来的字节数组转换成十六进制的字符串形式并返回
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private static String toHex(byte[] buffer){
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StringBuffer sb = new StringBuffer(buffer.length * 2);
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for (int i = 0; i < buffer.length; i++){
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sb.append(Character.forDigit((buffer & 0xf0) >> 4, 16));
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sb.append(Character.forDigit(buffer & 0x0f, 16));
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}
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return sb.toString();
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}
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}
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