滿足條件時如何停止運行線程？

Question

我想要一些有關在條件滿足后如何停止線程的建議。

這是我的代碼：

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();
        }
    }

}

這是我在main方法中創建的2個Animal對象的輸出：

即使宣布獲勝者，線程仍在繼續（在這種情況下，本地兔是獲勝者）。 我的問題是，在滿足條件時如何停止其他線程？ 我嘗試了interrupted（）方法，但看不到任何區別。

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原語即可停止線程。 您只需要退出while循環。

這是修改后的運行

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

如果找到贏家，只需退出循環。

   @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 );

    }

我執行了這個並得到了：

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

檢查每個循環中的條件，如果滿足，請中斷該循環，然后線程將停止。

interrupt()一個線程只是用來設置中斷標志，其他都沒有改變，可以通過isInterrupted()檢查該值

一般而言，除非自己希望，否則線程無法停止。