java 日期加8小时

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMddHHmmss");

public string dayAd8(String d){
	Date parse = null;
	parse = simpleDateFormat.parse(d);
	Calendar calendar = Calendar.getInstance();
	calendar.setTime(parse);
	calendar.set(Calendar.HOUR,calendar.get(Calendar.HOUR) + 8);
	return simpleDateFormat.format(calendar.getTime());
}