执行两个线程，当主线程继续时，一个线程等待另一个线程

Question

我如何启动两个线程，其中thread1首先执行，thread2在thread1结束时启动，而主方法线程可以在不锁定其他两个线程的情况下继续工作？

我尝试了join()，但是它需要从线程调用，线程必须等待另一个线程，没有办法执行类似thread2.join(thread1)的操作；因此，如果我在main（）中调用join，我将有效地停止主线程的执行，而不仅仅是Thread2的执行。

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

public class Test
{
    public static void main(String args[]) throws InterruptedException
    {
        System.out.println(Thread.currentThread().getName() + " is Started");

        class TestThread extends Thread
        {
            String name;
            public TestThread(String name)
            {
                this.name = name;
            }

            @Override
            public void run()
            {
                try
                {
                    System.out.println(this + " is Started");
                    Thread.sleep(2000);
                    System.out.println(this + " is Completed");
                }
                catch (InterruptedException ex)  {  ex.printStackTrace(); }
            }

            @Override
            public String toString()  { return "Thread " + name; }
        }

        ExecutorService executor = Executors.newCachedThreadPool();
        executor.execute(new TestThread("1"));

        boolean finished = executor.awaitTermination(1, TimeUnit.HOURS);

        if(finished)
        {
           //I should execute thread 2 only after thread 1 has finished
            executor.execute(new TestThread("2"));
        }

        //I should arrive here while process 1 and 2 go on with their execution
        System.out.println("Hello");
    }
}

#编辑：为什么我需要这个：

我需要这样做，因为Thread1将元素从一个数据库表复制到另一个数据库中，thread2必须复制一个链接表，该链接表引用从Thread1复制的表。因此，只有当thread1完成时，thread2才必须开始填充其链接表，否则数据库将给出完整性错误。现在想象一下，由于复杂的链接表，我有几个不同优先级的线程，您有一个想法。

Answer 1

第二个线程可以像这样自定义（将前一个线程作为参数）：

public static void main(String[] a) {
    Thread first = new Thread(new Runnable() {
        @Override
        public void run() {

        }
    });

    Thread second = new MyThread(first);
    first.start();
    second.start();

    //continue executing
}

public static class MyThread extends Thread {

    private Thread predecessor;

    public MyThread(Thread predecessor) {
        this.predecessor = predecessor;
    }

    public void run() {
        if (predecessor != null && predecessor.isAlive()) {
            try {
                predecessor.join();
            } catch (InterruptedException e) {}
        }
        //do your stuff
    }
}