Java线程

public class MyThread extends Thread{
    
    //整个的构造函数就跑在主线程中
    //仅仅在run方法中的程序才跑在MyThread的线程中。
    public MyThread(){
        print("MyThread Construct Before");
        start();
        print("MyThread Construct After");
    }
    
    @Override
    public void run(){
        int i = 0;
        while(true){
            i++;
            if(i<3){
                print("MyThread");
                try {
                    sleep(1000);
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }else{
                return;
            }
        }
    }
    //在哪里调用此函数，此函数就跑在哪个线程中
    private void print(String tag){
        System.out.println(tag+":"+Thread.currentThread().getId());
    }
}

public class ThreadTest {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println("Main:"+Thread.currentThread().getId());
        MyThread m = new MyThread();
        try {
            m.join();//主线程挂起，直到线程m结束才恢复
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        System.out.println("Done");
    }

}
//console output
Main:1
MyThread Construct Before:1
MyThread Construct After:1
MyThread:8
MyThread:8
Done