start（）不调用run（）方法

Question

    class Player implements Runnable{
        Thread t = new Thread();

        public Player(String name) {
            t.setName(name);
            t.start();
    }


    @Override
    public void run() {
        System.out.println(t.getName() + "starts the race.");
        for(int i = 0; i<3; i++)
        {
            System.out.println(t.getName() + " crossed " + i + " obstacle.");
        }
        System.out.println(t.getName() + " finishes the race.");
    }
}

class Competition {
    public static void main(String[] args){
        Player player1 = new Player("Cercei");
        Player player2 = new Player("Jamie");
        Player player3 = new Player("Tyrion");
    }
}

在下面的代码中编辑Player类，以便代码给出预期的输出。不要只打印预期的输出。不要编辑比赛类。不允许在Player类中添加任何变量。只添加必要的方法。您的代码会给出与预期输出完全相同的输出吗？解释原因。

class Player implements Runnable{
Thread t;
}
class Competition{
public static void main(String[] args){
Player player1 = new Player("Cercei");
Player player2 = new Player("Jamie");
Player player3 = new Player("Tyrion");
}
}

Answer 1

您需要告诉类播放器中的线程t它应该运行的目标runnable是什么。

根据您的设计，目标runnable是player类本身(this):

class Player implements Runnable {
    Thread t;

    public Player(String name) {
        t = new Thread(this); //<-- the target Runnable of the Thread t is the instance of Player itself
        t.setName(name);
        t.start();
    }

    @Override
    public void run() {
        System.out.println(t.getName() + "starts the race.");
        for (int i = 0; i < 3; i++) {
            System.out.println(t.getName() + " crossed " + i + " obstacle.");
        }
        System.out.println(t.getName() + " finishes the race.");
    }
}

在当前代码中，您将线程T初始化为New Thread()，但是您没有提供任何Runnabletarget，因此线程的.start()方法什么也不做。