set aCalend to current application’s NSCalendar’s currentCalendar()
set aDate to current application’s NSDate’s |date|()

set aYear to aCalend’s component:(current application’s NSCalendarUnitYear) fromDate:aDate
set aYearStr to numToZeroPaddingStr(aYear, 4, "0") of me

set aMonth to aCalend’s component:(current application’s NSCalendarUnitMonth) fromDate:aDate
set aMonthStr to numToZeroPaddingStr(aMonth, 2, "0") of me

set aDay to aCalend’s component:(current application’s NSCalendarUnitDay) fromDate:aDate
set aDayStr to numToZeroPaddingStr(aDay, 2, "0") of me

set dStr to aYearStr & aMonthStr & aDayStr
–> "20171219"

–整数の値に指定桁数ゼロパディングして文字列で返す
on numToZeroPaddingStr(aNum as integer, aDigit as integer, paddingChar as text)
　　set aNumForm to current application’s NSNumberFormatter’s alloc()’s init()
　　aNumForm’s setPaddingPosition:(current application’s NSNumberFormatterPadBeforePrefix)
　　aNumForm’s setPaddingCharacter:paddingChar
　　aNumForm’s setMinimumIntegerDigits:aDigit
　　
　　set bNum to current application’s NSNumber’s numberWithInt:aNum
　　set aStr to aNumForm’s stringFromNumber:bNum
　　
　　return aStr as text
end numToZeroPaddingStr