java中UTC转Date或者时间戳

public static long utcToTimestamp(DateTime dataTime) throws ParseException {
   SimpleDateFormat df2 = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
   df2.setTimeZone(TimeZone.getTimeZone("UTC"));
   Date date = df2.parse(dataTime.toString());
   return date.getTime();
}