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;@Overridepublic 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;}}}}