java - 在多线程中 : How to determine which thread stops first

Question

编写一个扩展 Thread 的名为 RaceHorse 的类。每个 RaceHorse 都有一个名称和显示名称 5000 次的 run() 方法。编写一个实例化 2 个 RaceHorse 对象的 Java 应用程序。最后完成的赛马为输家。

这就是问题。 我已经为两个运行线程的两个类编写了代码 以下是代码:

赛马

class RaceHorse extends Thread
{
    public String name;
    public RaceHorse(String name)
    {
        this.name = name;
    }
    public void run()
    {
        for(int i = 1 ; i <= 5000; i++)
        {
            System.out.println(i+"  "+name);
        }
        System.out.println(name+" finished.");
    }
}

运行者

class Runner{
    public static void main(String args[])
    {
        RaceHorse obj = new RaceHorse("Lol");
        RaceHorse obj2 = new RaceHorse("BOL");
        Thread t = new Thread(obj);
        Thread t2 = new Thread(obj2);
        t.start();
        t2.start();
    }
}

现在我的问题是我无法找到哪一个线程先完成，哪一秒完成，即哪匹马赢了，哪匹马输了。!

Answer 1

首先:您的RaceHorse 对象本身就是线程。您应该可以说 obj.start(); 并且它也能正常工作。因此，完全删除 t 和 t2。

接下来，您需要通过某种方式通知主线程获胜者。

public void run()
{
    ... your loop stuff ...
    // this is how we're going to do the notification.
    Runner.done();
}

public class Runner
{
    private static RaceHorse winner = null;
    synchronized static void done()
    {
        // Threads calling this are going to be RaceHorse objects.
        // Now, if there isn't already a winner, this RaceHorse is the winner.
        if (winner == null) winner = (RaceHorse) Thread.currentThread();
    }

    public static void main(String[] args)
    {
         ... create the horses ...
         // start the horses running
         obj.start();
         obj2.start();

         // wait for them to finish
         obj.join();
         obj2.join();

         System.out.println(winner.name + " wins!");
    }
}