java 計算兩個時間的時間差

    /**
    * startDate起始日期
    * endDate截止日期
    * dateType  日期類型 SECOND/MINUTE/HOUR/DAY/MONTH/YEAR
    */
   public static int dateTimeNums(Date startDate,Date endDate,String dateType) {
      String fmtStr = null;
      int timeNum = 3600 * 24;
      switch(dateType){
         case "SECOND":
            timeNum = 1;
            break;
         case "MINUTE":
            timeNum = 60;
            break;
         case "HOUR" :
            timeNum = 3600;
            break;
         case "DAY" :
            timeNum = 3600 * 24 ;
            break;
         case "MONTH" :
            timeNum = 3600 * 24 * 30;
            break;
         case "YEAR" :
            timeNum = 3600 * 24 * 365 ;
            break;
         default :
            break;
      }

      Calendar startCal = Calendar.getInstance();
      Calendar endCal = Calendar.getInstance();
      startCal.setTime(startDate);
      endCal.setTime(endDate);
     
      int nums = ((int)(endCal.getTime().getTime()/1000)-(int)(startCal.getTime().getTime()/1000))/timeNum;//換算成毫秒後再換成秒相減。
      return nums;
   }