/**
* 判断两个时间是否同一天
* @param string $date1 Y-m-d
* @param string $date2 Y-m-d
* @return bool
*/
public static function isSameDay($date1, $date2) {
$day1 = self::dateTime(strtotime($date1)) ;
$day2 = self::dateTime(strtotime($date2));
return $day1 == $day2;
}