定时器

public class Demo {
    private long time;//间隔的时间
    private Runnable task;//指定的任务
    private boolean flag = true;
    private Thread th = null;//默认为null
    public static void main(String[] args) {
        Demo de=new Demo(2L,new person());
    }
    public Demo(long time, Runnable task) {
        this.time = time;
        this.task = task;
    }
    
    public void start() {
        if(th == null) {
            // 一旦调用了start()方法后，th就不会在是null了。
            th = new Thread(new Runnable() {
                public void run() {
                    while(flag) {
                        task.run();
                        try {
                            Thread.sleep(time);
                        } catch(InterruptedException e) {}
                    }
                }
            });
            th.start();
        } else {
            throw new RuntimeException("定时器已经启动，不能再次启动！");
        }
    }
    
    public void stop() {
        this.flag = false;
    }


}

public class Test {
    public static void main(String[] args) throws InterruptedException {
        MyTimer mt = new MyTimer(2000, new Runnable() {
            public void run() {
                System.out.println("Hello World!");
            }
        });
        mt.start();
        Thread.sleep(10000);
        mt.stop();
    }
}

青春  22:34:17