code: public static long betweenMs(Date beginDate, Date endDate) {
  		return new DateBetween(beginDate, endDate).between(DateUnit.MS);
  	}
docs: 判断两个日期相差的毫秒数
  
  @param beginDate 起始日期
  @param endDate 结束日期
  @return 日期差
  @since 3.0.1