android时间精确到毫秒calendar

Calendar ca = Calendar.getInstance();
int year = ca.get(Calendar.YEAR);
int month = ca.get(Calendar.MONTH)+1;
int day = ca.get(Calendar.DAY_OF_MONTH);
int hour = ca.get(Calendar.HOUR);
int min = ca.get(Calendar.MINUTE);
int s = ca.get(Calendar.SECOND);
int m = ca.get(Calendar.MILLISECOND);