多线程：线程休眠

线程休眠

• sleep(时间）指定当前线程阻塞的毫秒数
• sleep存在异常interruptedException
• sleep时间达到后线程进入就绪状态
• sleep可以模拟网络延时，倒计时等
• 每个对象都有一个锁，sleep不会释放锁
• 模拟延时：

package exception.Demo03;
//模拟网络延时,放大问题的发生性
public class TestSleep implements Runnable{

    //票数
    private int ticketNums = 10;
    @Override
    public void run() {
        while(true) {
            if(ticketNums<=0){
                break;
            }
            //模拟延时

            try {
                Thread.sleep(200);
            } catch (InterruptedException e) {
                throw new RuntimeException(e);
            }

            System.out.println(Thread.currentThread().getName()+"---->拿到了第"+ticketNums--+"票");
        }

    }

    public static void main(String[] args) {
        TestSleep ticket = new TestSleep();
        new Thread(ticket,"小明").start();
        new Thread(ticket,"老师").start();
        new Thread(ticket,"王牛党").start();

    }
}

• 模拟倒计时：

package exception.Demo03;
//模拟倒计时
public class TestSleep2 {
    public static void main(String[] args) {
        try {
            tenDown();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }
    public static void tenDown() throws InterruptedException{
        int num = 10;
        while(true){
            Thread.sleep(1000);
            System.out.println(num--);
            if(num<=0){
                break;
            }
        }
    }
}

• 模拟系统时间：

package exception.Demo03;

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

public class TestSleep3 {
    //模拟系统时间
        public static void main(String[] args) {
            //打印当前系统时间
            Date startTime = new Date(System.currentTimeMillis());//获取系统当前时间
            while (true){
                try {
                    Thread.sleep(1000);
                    System.out.println(new SimpleDateFormat("HH:mm:ss").format(startTime));
                    startTime = new Date(System.currentTimeMillis());//更新当前时间
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        }
        public static void tenDown() throws InterruptedException{
            int num = 10;
            while(true){
                Thread.sleep(1000);
                System.out.println(num--);
                if(num<=0){
                    break;
                }
            }
        }
    }