class DelayThread exends Thread { private static int count=0; private int no; private int delay; public DelayThread(){ count++; no=count; } public void run(){ try{ for (int i=0;i<10;i++){ delay=(int)(Math.random()*5000); sleep(delay); System.out.println(“线程”+no+“ 的延迟时间是 ”+delay); } }catch(InterruptedException e){} } } public class MyThread{ public static void main(String args[]){ DelayThread thread1=new DelayThread(); DelayThread thread2=new DelayThread(); thread1.start(); thread2.start(); try{ Thread.sleep(1000);} catch(InterruptedException e){ System.out.println(“线程出错！”); } } } 将上列程序利用Runnable接口改写，并上机检验。

下面是使用 Runnable 接口改写的程序：

class DelayRunnable implements Runnable {
    private static int count = 0;
    private int no;
    private int delay;

    public DelayRunnable() {
        count++;
        no = count;
    }

    public void run() {
        try {
            for (int i = 0; i < 10; i++) {
                delay = (int) (Math.random() * 5000);
                Thread.sleep(delay);
                System.out.println("线程" + no + " 的延迟时间是 " + delay);
            }
        } catch (InterruptedException e) {
        }
    }
}

public class MyThread {
    public static void main(String args[]) {
        DelayRunnable dr1 = new DelayRunnable();
        DelayRunnable dr2 = new DelayRunnable();
        Thread thread1 = new Thread(dr1);
        Thread thread2 = new Thread(dr2);
        thread1.start();
        thread2.start();
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            System.out.println("线程出错！");
        }
    }
}

改写后的程序逻辑和原程序一致，只是将 DelayThread 类改为 DelayRunnable 类，并且创建线程时使用了 Runnable 接口的实现类作为参数。在主线程中也需要使用 Thread.sleep() 方法等待子线程执行完毕。