計算小時數差

//求今天剩下小時數
  java.sql.Timestamp nowtime=new Timestamp(System.currentTimeMillis());
  java.util.Date date2=formatter.parse(nowtime.toString());
  java.sql.Timestamp nowtime1= new Timestamp(date2.getTime());
  double nowDiffer=24-(double)(nowtime.getTime()-nowtime1.getTime())/3600000;