code: public static int sec(Date d) {
          Calendar c = C(d);
          int sec = c.get(Calendar.HOUR_OF_DAY) * 3600;
          sec += c.get(Calendar.MINUTE) * 60;
          sec += c.get(Calendar.SECOND);
          return sec;
      }
docs: 返回时间对象在一天中的秒数
  
  @param d
  时间对象
  
  @return 时间对象在一天中的秒数