如何让 AtomicInteger 在 Runnable 类中工作

Question

我用 Java 编写了这段代码Runnable，但我的教授希望我添加AtomicInteger，以便不存在线程干扰。我该如何去做呢？我尝试查找如何在代码中使用它的示例，但我不知道在这种情况下该怎么做。public class GarageWorker {    public static void main(String[] args) {        System.out.println("We are going to count the vehicles in the garage");        System.out.println();        System.out.println("There are 50 vehicles in the garage to start with!");        System.out.println();        GarageWorker garage = new GarageWorker(50);        Runnable vehicleEnter = garage.new Enter();        Runnable vehicleExit = garage.new Exit();        Thread thread1 = new Thread(vehicleEnter);        Thread thread2 = new Thread(vehicleExit);        thread1.start();        thread2.start();    }    public GarageWorker(int initialCarCount) {        counter = initialCarCount;    }    public int counter;    public class Enter implements Runnable {        public Enter() {        }        public int increaseVehicleCount() {            return ++counter;        }        public void run() {            while (counter < 100) {                System.out.println("One vehicle entered the garage now there are " + increaseVehicleCount());            }        }    }    public class Exit implements Runnable {        public Exit() {        }        public int decreaseVehicleCount() {            return --counter;        }        public void run() {            while (counter > 0) {                System.out.println("One vehicle left the garage now there are " + decreaseVehicleCount());            }        }    }}代码运行良好，但我的教授希望我将AtomicInteger类实现到代码中。

Answer 1

我猜你的教授希望你counter改成AtomicInteger. 首先，您需要导入AtomicInteger并更改构造函数的声明counter以反映这一点。

import java.util.concurrent.atomic.AtomicInteger;

public GarageWorker(int initialCarCount) {

    counter = new AtomicInteger(initialCarCount);

}

public AtomicInteger counter;

另外，您想要更改increaseVehicleCount和decreaseVehicleCount方法以便使用AtomicInteger代替int。

public int increaseVehicleCount() {

    return counter.incrementAndGet();

}

public int decreaseVehicleCount() {

    return counter.decrementAndGet();

}

incrementAndGet以及正如decrementAndGet他们所说：它们递增（或递减）并随后返回新值。