java中取得十五分钟之后的时间

String time="12:00:00"

DateFormat df = new SimpleDateFormat("HH:mm:dd");

Date date = null;
try {
date = df.parse(time);
} catch (ParseException e) {
e.printStackTrace();
}
Date afterDate = new Date(date.getTime()+900000);
System.out.println("dateafter is :" + afterDate);