code: public static String formatDurationOnSecond(@NotNull Date startDate, @NotNull Date endDate) {
  		return DurationFormatUtils.formatDuration(endDate.getTime() - startDate.getTime(), "HH:mm:ss");
  	}
docs: 按HH:mm:ss格式，格式化时间间隔
  
  endDate必须大于startDate，间隔可大于1天
  
  @see DurationFormatUtils