寫cookie

  Cookie cookie = new Cookie("username", java.net.URLEncoder.encode(username,"UTF-8"));
   cookie.setMaxAge(50*60);//不設定的話，則cookies不寫入硬碟,而是寫在記憶體,只在當前頁面有用,以秒為單位   
   response.addCookie(cookie);

讀cookie

Cookie cookies[] = request.getCookies();   
 if (cookies != null)   
 {   
     for (int i = 0; i < cookies.length; i++)   
     {   
       
         if (cookies[i].getName().equals("username")) 
          
         {  
          username=java.net.URLDecoder.decode(cookies[i].getValue().trim(),"UTF-8");