筆記20200518：多線程【線程休眠_sleep】

package com.chengguo.線程;

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

/**
 * 模擬倒計時
 */
public class Demo_20200518001_Sleep {
    public static void main(String[] args) {
        try {
            tenDown();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        System.out.println("================================");
        /**
         * 打印系統當前時間
         */
        //獲取系統當前時間
        Date startTime = new Date(System.currentTimeMillis());
        //
        while (true) {
            try {

                Thread.sleep(1000);
                System.out.println(new SimpleDateFormat("HH:mm:ss").format(startTime));
                //更新系統時間
                startTime = new Date(System.currentTimeMillis());

            } catch (InterruptedException e) {
                e.printStackTrace();
            }

        }
    }

    public static void tenDown() throws InterruptedException {
        int num = 10;
        while (true) {
            Thread.sleep(1000);
            System.out.println("倒計時：" + num-- + "s");
            if (num <= 0) {
                break;
            }
        }
    }
}