Date相減

/**
  * @param 要轉換的毫秒數
  * @return 該毫秒數轉換爲 * days * hours * minutes * seconds 後的格式
  * @author fy.zhang
  */
 public static String formatDuring(long mss) {
      long days = mss / (1000 * 60 * 60 * 24);
      long hours = (mss % (1000 * 60 * 60 * 24)) / (1000 * 60 * 60);
      long minutes = (mss % (1000 * 60 * 60)) / (1000 * 60);
      long seconds = (mss % (1000 * 60)) / 1000;
      return days + " days " + hours + " hours " + minutes + " minutes " + seconds + " seconds ";
 }

 /**
  * @param begin 時間段的開始
  * @param end     時間段的結束
  * @return     輸入的兩個Date類型數據之間的時間間格用* days * hours * minutes * seconds的格式展示
  * @author fy.zhang
  */
 public static String formatDuring(Date begin, Date end) {
      return formatDuring(end.getTime() - begin.getTime());
 }