在原有時間上增加5分鐘，然後計算與當前時間之差

String enableTime="2012-08-28 15:12:00";
  System.out.println("enableTime:" + enableTime);  //2012-08-28 15:12:00

  SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
        try {  
            Date lastTime = sdf.parse(enableTime);
            System.out.println("lastTime is:" + lastTime);
            Calendar cal=Calendar.getInstance();
            cal.setTime(lastTime);
            cal.add(Calendar.MINUTE,+5);
            lastTime=cal.getTime();
            System.out.println(lastTime);
            System.out.println("5 minutes after(or before) is "+sdf.format(lastTime));
            cal=null;
            Date systemTime = new Date();
            if(lastTime.after(systemTime)){
             //獲取兩個時間的相隔多少分鐘
             long between = lastTime.getTime() - systemTime.getTime();
             System.out.println(between);
             int time = (int)between/(60*60*10);
             System.out.println("禁止時間在系統時間之後，您還需要等待"  + time + "分鐘");
            }
        } catch (Exception e) {  
         e.printStackTrace();
        }