자바 쿠키 는 사용자 계 정 정보 로 컬 저장 을 실현 합 니 다.

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; 

 /*  * 2007.09.21 by lyhapple  * */  

public class CookieUtil {         

//  cookie  cookieName        

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

 //  cookie               

 private final static String webKey = “itcast”;          

 //  cookie        ，               

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

 //  Cookie    --------------------------------------------------------------------------------------------------------         // CheckLogonServlet.java             

//     user                            

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

 //cookie                    

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

 //MD5                       

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

  //         Cookie                

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

 //    Cookie    BASE64                  

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

  //    Cookie               

 Cookie cookie = new Cookie(cookieDomainName, cookieValueBase64);               

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

 //cookie                         

 cookie.setPath("/");               

 //                     

 response.addCookie(cookie);       

  }                 

 //  Cookie,        --------------------------------------------------------------------------------------------       

  // Filter        , AutoLogonFilter.java        

 public static void readCookieAndLogon(HttpServletRequest request, HttpServletResponse response,  FilterChain chain) 

throws IOException, ServletException,UnsupportedEncodingException{                         

//  cookieName cookieValue  

Cookie cookies[] = request.getCookies();                      

 String cookieValue = null;                      

 if(cookies!=null){                            

  for(int i=0;i                                    

 if (cookieDomainName.equals(cookies[i].getName())) {                            

                cookieValue = cookies[i].getValue();                                 

           break;                                   

  }                              }                

       }                      

 //  cookieValue  ,  ,                    

   if(cookieValue==null){                      

        return;            

           }                          

      //  cookieValue   ,                     

   //    CookieValue  Base64               

   String cookieValueAfterDecode = new String (Base64.decode(cookieValue),"utf-8");       

                         //          ,      ,        3,               

       String cookieValues[] = cookieValueAfterDecode.split(":");            

    if(cookieValues.length!=3){                  

     response.setContentType("text/html;charset=utf-8");                    

   PrintWriter out = response.getWriter();                      

 out.println("             ...");                   

    out.close();                     

  return;            

    }                              

  //         ,     Cookie         

       long validTimeInCookie = new Long(cookieValues[1]);          

      if(validTimeInCookie < System.currentTimeMillis()){                   

    //  Cookie                      

 clearCookie(response);                   

    response.setContentType("text/html;charset=utf-8");         

              PrintWriter out = response.getWriter();           

            out.println("");  Cookie    ,              

              out.close();              

         return;          

      }                          

      //  cookie     ,             ,        

        String username = cookieValues[0];                  

              //                         

         UserDAO ud = DaoImplFactory.getInstance();        

        User user = ud.selectUserByUsername(username);        

                        //  user     ,     ,     +  +    + webSiteKey  MD5               

   if(user!=null){                       

String md5ValueInCookie = cookieValues[2];                      

 String md5ValueFromUser =getMD5(user.getUserName() + ":" + user.getPassword()                                     + ":" + validTimeInCookie + ":" + webKey);              

         //    Cookie  MD5    ,    ,  Session,      ,                      

        if(md5ValueFromUser.equals(md5ValueInCookie)){      

                        HttpSession session = request.getSession(true);    

                          session.setAttribute("user", user);                      

        chain.doFilter(request, response);                     

  }               

 }

else

{         

//                            

 response.setContentType("text/html;charset=utf-8");                

       PrintWriter out = response.getWriter();                  

     out.println("cookie    ！");                     

  out.close();       

  return;  

}      

   }               

   //     ,  Cookie,         ------------------------------------------------------------        

 public static void clearCookie( HttpServletResponse response){                

Cookie cookie = new Cookie(cookieDomainName, null);              

  cookie.setMaxAge(0);               

 cookie.setPath("/");               

 response.addCookie(cookie);        

 }  

//  Cookie      MD5     ----------------------------------------------------------------------------              

  public static String getMD5(String value) {                      

 String result = null;                      

 try{                          

    byte[] valueByte = value.getBytes();                    

          MessageDigest md = MessageDigest.getInstance("MD5");               

               md.update(valueByte);                         

     result = toHex(md.digest());                    

   } catch (NoSuchAlgorithmException e2)

{                             

 e1.printStackTrace();  

}                      

 return result;              

  }           

//                                      

    private static String toHex(byte[] buffer){                   

    StringBuffer sb = new StringBuffer(buffer.length * 2);            

           for (int i = 0; i < buffer.length; i++){                

              sb.append(Character.forDigit((buffer[i] & 0xf0) >> 4, 16));                         

     sb.append(Character.forDigit(buffer[i] & 0x0f, 16));                 

      }                  

     return sb.toString();          

      } 

 }