code: public static Date dateReservedMonth000(Date date) {
          Calendar calendar = Calendar.getInstance();
          calendar.setTime(date);
  
          return dateReservedMonth000(calendar);
      }
docs: 将一个日期的日,时,分,秒,毫秒调整为最小值
  
  @param date 一个日期
  @return 被转化后的日期
  @see #dateReservedMonth000(Calendar)