java多线程实现假期倒计时

以下是一个Java多线程实现假期倒计时的例子：

import java.text.SimpleDateFormat;
import java.util.Date;

public class CountdownThread extends Thread {
    private int days;

    public CountdownThread(int days) {
        this.days = days;
    }

    @Override
    public void run() {
        Date startTime = new Date(System.currentTimeMillis());
        while (days > 0) {
            try {
                Thread.sleep(1000);
                System.out.println("距离假期还有 " + days + " 天");
                startTime = new Date(System.currentTimeMillis());
                days--;
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println("假期开始！");
    }

    public static void main(String[] args) {
        CountdownThread countdownThread = new CountdownThread(7);
        countdownThread.start();
    }
}