java 多线程 join应用

package thread;

/**
 * 3个线程T1,T2,T3,要求T1,T2,T3按顺序执行
 */
public class Thread8Test {
    
    private static class Thread1 extends Thread
    {
        @Override
        public void run() {

            System.out.println("线程1");
        }
    }

    private static class Thread2 extends Thread
    {
        @Override
        public void run() {
            try {
                thread1.join();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("线程2");
        }
    }

    private static class Thread3 extends Thread
    {
        @Override
        public void run() {
            try {
                thread2.join();
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("线程3");
        }
    }

    static Thread1 thread1;
    static Thread2 thread2;
    static Thread3 thread3;

    public static void main(String[] args)  {
        thread1 = new Thread1();
        thread2 = new Thread2();
        thread3 = new Thread3();
        
        thread3.start();
        thread2.start();
        thread1.start();

    }
}