自己Cookie写的自动登录功能 包含BASE64 和MD5的使用

sql表

username  password字段

User类

有 id username password等字段

Service有一函数

 @Override

 public User findUser(String username)
 {
     return userDao.findUser(username);
 }

实现

     @Override
     public User findUser(String username) {
         try {
             return qr.query("select * from user where username=?", new BeanHandler<User>(User.class),username);
         } catch (SQLException e) {
             throw new DaoException(e);
         }
     }

Utils

WEBUtils.java

 package cn.itcast.util;

 import java.lang.reflect.InvocationTargetException;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;

 import javax.servlet.http.Cookie;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import org.apache.commons.beanutils.BeanUtils;

 import sun.misc.BASE64Encoder;

 public class WebUtils {

     public static <T> T fillBean(HttpServletRequest request,
             Class<T> clazz) {
         try {
             T t=clazz.newInstance();
             BeanUtils.populate(t,request.getParameterMap());
             return t;
         } catch(Exception e) {
             throw new RuntimeException(e);
         }
     }

     public static void addAutoLoginFunction(HttpServletRequest request,
             HttpServletResponse response) {

         String username=request.getParameter("username");
         String password=request.getParameter("password");
         //把帐号BASE64加密 _ 密码双次md5加密， 所以比较的时候 数据库中密码取出md5加密再和这个比较

         String encodeUsername=new BASE64Encoder().encode(username.getBytes());
         String encodePassword=Md5Util.md5(password);
         System.out.println("存入数据库 帐号:"+username);
         System.out.println("存入数据库 密码:"+password);
         System.out.println("存入Cookie 帐号:"+encodeUsername);
         System.out.println("存入Cookie密码:"+encodePassword);
         Cookie c=new Cookie("loginInfo",encodeUsername+"_"+encodePassword);
         c.setMaxAge(10000);
         c.setPath(request.getContextPath());
         response.addCookie(c);
     }
     //删除Cookie
     public static void removeAutoLoginCookie(HttpServletRequest request,
             HttpServletResponse response) {
         Cookie cs[]=request.getCookies();
         if(cs!=null)
         {
             for(Cookie c:cs)
             {
                 if(c.getName().equals("loginInfo"))
                 {
                     Cookie cookie=new Cookie("loginInfo",null);
                     cookie.setMaxAge(0);
                     cookie.setPath(request.getContextPath());
                     response.addCookie(cookie);
 //                    c.setMaxAge(0);
 //                    c.setPath(request.getContextPath());
                     System.out.println("删除Cookie");
                     return;
                 }
             }
         }
     }

 }

MD5Util.java

 package cn.itcast.util;

 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;

 import sun.misc.BASE64Encoder;

 public class Md5Util {
     public static String md5(String message){
         try{
             MessageDigest md = MessageDigest.getInstance("md5");
             byte b[] = md.digest(message.getBytes());
             return new BASE64Encoder().encode(b);
         }catch(Exception e){
             throw new RuntimeException(e);
         }
     }
 }

Servlet中 由doGet()引出以下两个方法 operation=login   operation=logout

    private void logout(HttpServletRequest request, HttpServletResponse response) throws IOException {
        //移除Cookie 去除自动登录功能
        WebUtils.removeAutoLoginCookie(request,response);
        request.getSession().invalidate();
        response.sendRedirect(request.getContextPath());
    }

    private void login(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String username=request.getParameter("username");
        String password=request.getParameter("password");
        BusinessService serviceDao=new BusinessServiceImpl();
        password=Md5Util.md5(password);
        User user=serviceDao.login(username,password);
        if(null==user)
        {
            request.setAttribute("message", "用户名或者密码错误");
            request.getRequestDispatcher("/client/message.jsp").forward(request, response);
        }
        else
        {
            request.getSession().setAttribute("user", user);
            String autoLogin=request.getParameter("autologin");
            if(null!=autoLogin)
            {
                //添加自动登录功能
                WebUtils.addAutoLoginFunction(request,response);
            }
            response.sendRedirect(request.getContextPath());
        }
    }

filter过滤器中配置

 package cn.itcast.web.filter;

 import java.io.IOException;

 import javax.servlet.Filter;
 import javax.servlet.FilterChain;
 import javax.servlet.FilterConfig;
 import javax.servlet.ServletException;
 import javax.servlet.ServletRequest;
 import javax.servlet.ServletResponse;
 import javax.servlet.http.Cookie;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpSession;

 import sun.misc.BASE64Decoder;

 import cn.itcast.domain.User;
 import cn.itcast.service.BusinessService;
 import cn.itcast.service.impl.BusinessServiceImpl;
 import cn.itcast.util.Md5Util;

 public class AutoLoginFilter implements Filter {

     @Override
     public void init(FilterConfig filterConfig) throws ServletException {

     }

     @Override
     public void doFilter(ServletRequest req, ServletResponse resp,
             FilterChain chain) throws IOException, ServletException {

         HttpServletRequest request = (HttpServletRequest)req;
         HttpServletResponse response = (HttpServletResponse)resp;
         BusinessService bService=new BusinessServiceImpl();
         HttpSession session = request.getSession();
         User u = (User)session.getAttribute("user");
         if(null==u)////只有没有登录时才自动登录，已经登录了就不需要了
         {
             System.out.println("自动登录开始执行");
             //1、获取名称为loginInfo的cookie
             Cookie loginInfoCookie=null;
             Cookie cs[]=request.getCookies();
             if(null!=cs)
             {
                 for(Cookie c:cs)
                 {
                     if("loginInfo".equals(c.getName()))
                     {
                         loginInfoCookie=c;
                         break;
                     }
                 }
             }
             //2、有：取出cookie的值：用户名_加密的密码
             if(null!=loginInfoCookie)
             {
                 String usernamePassword=loginInfoCookie.getValue();
                 System.out.println("帐号密码整串:"+usernamePassword);
                 //3、拆出用户名和密码
                 String username=usernamePassword.split("\\_")[0];
                 String password=usernamePassword.split("\\_")[1];
                 //根据登录的时候 username password放入Cookie的原理
                 //username BASE64解密
                 username=new String(new BASE64Decoder().decodeBuffer(username));
                 System.out.println("Cookie的用户:"+username);
                 System.out.println("Cookie的密码:"+password);
                 User user=bService.findUser(username);
                 if(null!=user)
                 {
                     System.out.println("Cookie的用户:"+user.getUsername());
                     System.out.println("Cookie的密码:"+Md5Util.md5(user.getPassword()));
                     //4、再次验证用户名和密码是否正确（根据用户名查出密码，加密后再与cookie中的那个密码进行比对）
                     //将数据库查出的密码 md5加密和cookie中的密码相比
                     if(Md5Util.md5(user.getPassword()).equals(password))
                     {
                         //5、正确：得到用户对象，放到HttpSession中（自动登录）
                         session.setAttribute("user", user);
                         //自动登录搞定
                         System.out.println("自动登录完成");
                     }
                 }
             }
         }
         //放行
         chain.doFilter(request, response);
     }

     @Override
     public void destroy() {

     }

 }

web.xml中可以配置对指定的页面进行 自动登录的过滤器， 因为放到session中，所以不需要每个页面都过滤

url-pattern 配置 过滤地址