倒计时 countdown

import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.Timer;
import java.util.TimerTask;

public class Countdown {
    public static void main(String[] args) {
        final int secondsInMinute = 60;
        final int secondsInHour = 3600;
        final int secondsInDay = 86400;

        int year = 2012;
        int month = 12 - 1;
        int dayOfMonth = 22;
        int hourOfDay = 23;
        int minute = 59;
        int second = 59;

        Calendar calendar = new GregorianCalendar(year, month, dayOfMonth,
            hourOfDay, minute, second);
        final long targetTimeMillis = calendar.getTimeInMillis();
        final Timer timer = new Timer();
        timer.scheduleAtFixedRate(new TimerTask() {
            @Override
            public void run() {
                long difference = targetTimeMillis - System.currentTimeMillis();
                if (difference <= 0) {
                    timer.cancel();
                }
                long secondsDiff = difference / 1000;
                long days = secondsDiff / secondsInDay;
                long hours = secondsDiff % secondsInDay / secondsInHour;
                long minutes = secondsDiff % secondsInHour / secondsInMinute;
                long seconds = secondsDiff % secondsInMinute;
                System.out.println(String.format("%1$3d天%2$02d时%3$02d分%4$02d秒",
                    days, hours, minutes, seconds));
            }
        }, 0, 1000);
    }
}