满足条件时如何停止运行线程？

Question

我想要一些有关在条件满足后如何停止线程的建议。

这是我的代码：

public class Animal implements Runnable {
    private static boolean winner = false;
    private String name;
    private int position;
    private int speed;
    private long restMax;



    public Animal(String name, int position, int speed, long restMax) {

        this.name = name;
        this.position = position;
        this.speed = speed;
        this.restMax = restMax;
    }



    @Override
    public void run() {

        while (position < 100){
            position += speed;
            try {
                Thread.sleep((long) (0 + (Math.random()  * restMax)));
            } catch (InterruptedException e) {

                e.printStackTrace();
            }


        System.out.println(name + " is at position " + position );

    }
        if (position >= 100){
            winner = true;
            System.out.println(name + " is the winner of the race!");
            Thread.interrupted();
        }
    }

}

这是我在main方法中创建的2个Animal对象的输出：

即使宣布获胜者，线程仍在继续（在这种情况下，本地兔是获胜者）。 我的问题是，在满足条件时如何停止其他线程？ 我尝试了interrupted（）方法，但看不到任何区别。

Homegrown Rabbit is at position 5

Homegrown Rabbit is at position 10

Wild Turtle is at position 3

Wild Turtle is at position 6

Homegrown Rabbit is at position 15

Homegrown Rabbit is at position 20

Wild Turtle is at position 9

Wild Turtle is at position 12

Wild Turtle is at position 15

Homegrown Rabbit is at position 25

Wild Turtle is at position 18

Homegrown Rabbit is at position 30

Wild Turtle is at position 21

Homegrown Rabbit is at position 35

Wild Turtle is at position 24

Homegrown Rabbit is at position 40

Wild Turtle is at position 27

Wild Turtle is at position 30

Homegrown Rabbit is at position 45

Homegrown Rabbit is at position 50

Wild Turtle is at position 33

Homegrown Rabbit is at position 55

Wild Turtle is at position 36

Wild Turtle is at position 39

Homegrown Rabbit is at position 60

Wild Turtle is at position 42

Wild Turtle is at position 45

Homegrown Rabbit is at position 65

Wild Turtle is at position 48

Wild Turtle is at position 51

Homegrown Rabbit is at position 70

Homegrown Rabbit is at position 75

Wild Turtle is at position 54

Wild Turtle is at position 57

Wild Turtle is at position 60

Homegrown Rabbit is at position 80

Homegrown Rabbit is at position 85

Wild Turtle is at position 63

Wild Turtle is at position 66

Homegrown Rabbit is at position 90

Wild Turtle is at position 69

Wild Turtle is at position 72

Wild Turtle is at position 75

Homegrown Rabbit is at position 95

Wild Turtle is at position 78

Homegrown Rabbit is at position 100

Homegrown Rabbit is the winner of the race!

Wild Turtle is at position 81

Wild Turtle is at position 84

Wild Turtle is at position 87

Wild Turtle is at position 90

Wild Turtle is at position 93

Wild Turtle is at position 96

Wild Turtle is at position 99

Wild Turtle is at position 102

Wild Turtle is the winner of the race!

Answer 1

您不需要任何Thread原语即可停止线程。 您只需要退出while循环。

这是修改后的运行

public void run() 
{
    while (winner == false)
    {
        position += speed;
        System.out.println(name + " is at position " + position );

        if(position >= 100)
        {
            winner = true;
            System.out.println(name + " is the winner of the race!");
            break;
        }

        try 
        {
            Thread.sleep((long) (0 + (Math.random()  * restMax)));
        } 
        catch (InterruptedException e) 
        {
            e.printStackTrace();
        }
    }

}

Answer 2

如果找到赢家，只需退出循环。

   @Override
    public void run() {


        while (position < 100){
            position += speed;
            try {
                Thread.sleep((long) (0 + (Math.random()  * restMax)));
            } catch (InterruptedException e) {

                e.printStackTrace();
            }

           /* Since winner is static, once one thread sets this to true,
              other threads will stop their execution as well. */
           if (winner)
               break;
        System.out.println(name + " is at position " + position );

    }

我执行了这个并得到了：

rabbit is at position 2
horse is at position 5
rabbit is at position 4
horse is at position 10
horse is at position 15
horse is at position 20
horse is at position 25
horse is at position 30
rabbit is at position 6
horse is at position 35
rabbit is at position 8
horse is at position 40
horse is at position 45
horse is at position 50
horse is at position 55
horse is at position 60
horse is at position 65
horse is at position 70
horse is at position 75
horse is at position 80
horse is at position 85
horse is at position 90
horse is at position 95
horse is at position 100
horse is the winner of the race!

Answer 3

检查每个循环中的条件，如果满足，请中断该循环，然后线程将停止。

interrupt()一个线程只是用来设置中断标志，其他都没有改变，可以通过isInterrupted()检查该值

一般而言，除非自己希望，否则线程无法停止。