code: public static Integer getDayNumOfSeason(Date date) {
  
          if (date == null)
              return null;
  
          int day = 0;
          Date[] seasonDates = getSeasonDate(date);
          for (Date d : seasonDates) {
              day += getDayOfMonth(d);
          }
          return day;
      }
docs: 获取季度的天数
  @param date 时间({@link Date})
  @return 天数，如果date is null，将返回null