如何保證線程按順序執行

http://www.cnblogs.com/gongjian/p/6121518.html

/*
 有三個線程T1 T2 T3，如何保證他們按順序執行-轉載
在T2的run中，調用t1.join，讓t1執行完成后再讓T2執行
在T2的run中，調用t2.join，讓t2執行完成后再讓T3執行
*/
public class ThreadByOrder {

    static Thread t1 = new Thread(new Runnable() {

        @Override
        public void run() {
            System.out.println("t1");
        }
    });

    static Thread t2 = new Thread(new Runnable() {

        @Override
        public void run() {
            try {
                t1.join();
                Thread.sleep(500);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println("t2");
        }
    });

    static Thread t3 = new Thread(new Runnable() {

        @Override
        public void run() {
            try {
                t2.join();
                Thread.sleep(500);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            System.out.println("t3");
        }
    });
    public static void main(String[] args) {
        t1.start();
        t2.start();
        t3.start();

    }

}