gmdate處理excel導入時間問題

讀取excel檔案後發現，時間都是類似于這樣的數字：44410.405555556，那麼如何轉換成正常的時間

gmdate('Y/m/d',PHPExcel_Shared_Date::ExcelToPHP(44410.010416667);
           

ExcelToPHP方法如下

/**
     *    Convert a date from Excel to PHP
     *
     *    @param        integer        $dateValue            Excel date/time value
     *    @param        boolean        $adjustToTimezone    Flag indicating whether $dateValue should be treated as
     *                                                    a UST timestamp, or adjusted to UST
     *    @param        string         $timezone            The timezone for finding the adjustment from UST
     *    @return       integer        PHP serialized date/time
     */
    public static function ExcelToPHP($dateValue = 0, $adjustToTimezone = false, $timezone = null)
    {
        if (self::$excelBaseDate == self::CALENDAR_WINDOWS_1900) {
            $myexcelBaseDate = 25569;
            //    Adjust for the spurious 29-Feb-1900 (Day 60)
            if ($dateValue < 60) {
                --$myexcelBaseDate;
            }
        } else {
            $myexcelBaseDate = 24107;
        }

        // Perform conversion
        if ($dateValue >= 1) {
            $utcDays = $dateValue - $myexcelBaseDate;
            $returnValue = round($utcDays * 86400);
            if (($returnValue <= PHP_INT_MAX) && ($returnValue >= -PHP_INT_MAX)) {
                $returnValue = (integer) $returnValue;
            }
        } else {
            $hours = round($dateValue * 24);
            $mins = round($dateValue * 1440) - round($hours * 60);
            $secs = round($dateValue * 86400) - round($hours * 3600) - round($mins * 60);
            $returnValue = (integer) gmmktime($hours, $mins, $secs);
        }

        $timezoneAdjustment = ($adjustToTimezone) ?
            PHPExcel_Shared_TimeZone::getTimezoneAdjustment($timezone, $returnValue) :
            0;

        return $returnValue + $timezoneAdjustment;
    }