java - java multithreading:交通路口系统

我试图通过具有2个线程在Java中使用多线程，其中一个线程代表一辆汽车通过十字路口，另一条代表另一辆汽车等待通过十字路口。我的问题是car2打印出“ car2等待穿越”的次数比它应打印的次数多（它应该只打印6次）。我已经尝试过使用同步化功能，但这不起作用。它是一个非常简单的程序，我正尝试制作它来帮助自己了解多线程，如下所示。

public class Drive {
    public static Thread car1;
    public static Thread car2;

    public static void main(String[]args){

        Cars cars = new Cars();

        car1 = new Thread(cars, "car 1");
        car2 = new Thread(cars, "car 2");

        car1.start();
        car2.start();

    }
}

public class Cars implements Runnable{

    int distance = 0;

    public void increaseDistance(){
        distance ++;
    }

    public void race(){
        while(distance <= 5){

            if(Thread.currentThread().getName().equals("car 1")){
                System.out.println("Distance covered by " + Thread.currentThread().getName() + " is " + distance + " meters");
                increaseDistance();
            }

            if(Thread.currentThread().getName().equals("car 2")){

                System.out.println(Thread.currentThread().getName() + " is waiting to cross");
            }

        }

    }

    public void run(){
        race();
    }
}

输出即时消息低于...

car 2 is waiting to cross
car 2 is waiting to cross
car 2 is waiting to cross
car 2 is waiting to cross
car 2 is waiting to cross
Distance covered by car 1 is 0 meters
car 2 is waiting to cross
Distance covered by car 1 is 1 meters
Distance covered by car 1 is 2 meters
Distance covered by car 1 is 3 meters
Distance covered by car 1 is 4 meters
Distance covered by car 1 is 5 meters
car 2 is waiting to cross

它说“汽车2等待穿越”的位置应该打印出与“汽车1所覆盖的距离为x米”相同的时间，但是每次都随机打印吗？

最佳答案

car2的race（）方法不必在car1的crementDistance（）方法被调用后才执行一次。有可能多次调用此方法。欢迎来到不规则的调度世界。

您应该做的是使用条件来通知car2 car1调用了invokeDistance（），而car2应该在其race（）方法中等待此条件。
这将确保car2打印出预期的输出。

关于java - java multithreading:交通路口系统，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/36710555/