Java 两线程共享数据的多线程编程_Java_Multithreading

Java 两线程共享数据的多线程编程

java multithreading

Java 两线程共享数据的多线程编程,java,multithreading,Java,Multithreading,我应该制作一个程序，模拟汽车试图通过一条单行道的桥。汽车可以从桥的西侧和东侧来。以下是我到目前为止的情况：主要类别： package project4.pkg2; import java.util.Scanner; public class Project42 { static int wbCars = 0; static int ebCars = 0; static boolean check = true; static void setCheck(int

我应该制作一个程序，模拟汽车试图通过一条单行道的桥。汽车可以从桥的西侧和东侧来。以下是我到目前为止的情况：

主要类别：

package project4.pkg2;
import java.util.Scanner;
public class Project42 {
    static int wbCars = 0;
    static int ebCars = 0;
    static boolean check = true;

    static void setCheck(int i) {
        if (i == 0){
            check = false;
        }
        else
        {
            check = true;
        }
    }
    static boolean check() {
        return check;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Amount of west-bound cars: ");
        wbCars = in.nextInt();
        System.out.println("Amount of east-bound cars: ");
        ebCars = in.nextInt();

        WestBound myWest = new WestBound(wbCars);
        Thread westThread = new Thread(myWest);
        westThread.start();

        EastBound myEast = new EastBound(ebCars);
        Thread eastThread = new Thread(myEast);
        eastThread.start();
    }

}

package project4.pkg2;
import java.util.Scanner;
public class Project42 {
    static int wbCars = 0;
    static int ebCars = 0;
    static boolean check = true;

     static synchronized void setCheck(int i) {
        if (i == 0){
            check = false;
        }
        else
        {
            check = true;
        }
    }
    static synchronized boolean check() {
        return check;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Amount of west-bound cars: ");
        wbCars = in.nextInt();
        System.out.println("Amount of east-bound cars: ");
        ebCars = in.nextInt();

        WestBound myWest = new WestBound(wbCars);
        Thread westThread = new Thread(myWest);
        westThread.start();

        EastBound myEast = new EastBound(ebCars);
        Thread eastThread = new Thread(myEast);
        eastThread.start();
    }

}

东行班次：

package project4.pkg2;

import java.util.concurrent.TimeUnit;

class EastBound implements Runnable {

    int cars = Project42.ebCars;

    EastBound(int cars){
        super();
        this.cars = cars;
    }

    @Override
    public void run() {
        //System.out.println(cars + " <- cars");
        while (cars > 0 && Project42.check() == true){
                Project42.setCheck(0);
                System.out.println("An east-bound car is driving on the bridge.");
                try {
                TimeUnit.SECONDS.sleep(3);
                }
                catch (Exception e) {
                    System.out.println("Sumthin weird happened here.");
                }
                Project42.setCheck(1);
                System.out.println("The east-bound car has crossed the bridge.");
                cars--;  
        }
    }
}

package project4.pkg2;

import java.util.concurrent.TimeUnit;

public class WestBound implements Runnable {

    int cars = Project42.wbCars;

    WestBound(int cars){
        super();
        this.cars = cars;
    }

    @Override
    public void run() {
        //System.out.println("I made it this far!");
        while (cars > 0 && Project42.check() == true){
                Project42.setCheck(0);
                try {
                TimeUnit.SECONDS.sleep(1);
                }
                catch (Exception e) {
                    System.out.println("Sumthin weird happened here.");
                }

                System.out.println("A west-bound car is driving on the bridge.");

                try {
                TimeUnit.SECONDS.sleep(3);
                }
                catch (Exception e) {
                    System.out.println("Sumthin weird happened here.");
                }
                Project42.setCheck(1);
                System.out.println("The west-bound car has crossed the bridge.");
                cars--;
        }
    }
}

我的问题是在主课堂上，无论我先运行哪个线程（在本例中是我的westThread），只有我向西行驶的车辆通过，而没有一辆向东行驶的车辆通过。反之亦然，当我把东线程放在西线程之前

程序输出：

run:
Amount of west-bound cars: 
2
Amount of east-bound cars: 
3
A west-bound car is driving on the bridge.
The west-bound car has crossed the bridge.
A west-bound car is driving on the bridge.
The west-bound car has crossed the bridge.
BUILD SUCCESSFUL (total time: 9 seconds)

编辑：

谢谢你的帮助。对于有类似问题的未来观众，以下是我的解决方案：

主要类别：

package project4.pkg2;
import java.util.Scanner;
public class Project42 {
    static int wbCars = 0;
    static int ebCars = 0;
    static boolean check = true;

    static void setCheck(int i) {
        if (i == 0){
            check = false;
        }
        else
        {
            check = true;
        }
    }
    static boolean check() {
        return check;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Amount of west-bound cars: ");
        wbCars = in.nextInt();
        System.out.println("Amount of east-bound cars: ");
        ebCars = in.nextInt();

        WestBound myWest = new WestBound(wbCars);
        Thread westThread = new Thread(myWest);
        westThread.start();

        EastBound myEast = new EastBound(ebCars);
        Thread eastThread = new Thread(myEast);
        eastThread.start();
    }

}

package project4.pkg2;
import java.util.Scanner;
public class Project42 {
    static int wbCars = 0;
    static int ebCars = 0;
    static boolean check = true;

     static synchronized void setCheck(int i) {
        if (i == 0){
            check = false;
        }
        else
        {
            check = true;
        }
    }
    static synchronized boolean check() {
        return check;
    }

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.println("Amount of west-bound cars: ");
        wbCars = in.nextInt();
        System.out.println("Amount of east-bound cars: ");
        ebCars = in.nextInt();

        WestBound myWest = new WestBound(wbCars);
        Thread westThread = new Thread(myWest);
        westThread.start();

        EastBound myEast = new EastBound(ebCars);
        Thread eastThread = new Thread(myEast);
        eastThread.start();
    }

}

西行：

package project4.pkg2;

import java.util.concurrent.TimeUnit;

public class WestBound implements Runnable {

    int cars = Project42.wbCars;

    WestBound(int cars){
        super();
        this.cars = cars;
    }

    @Override
    public void run() {
        //System.out.println("I made it this far!");
        while (cars > 0){
            if (Project42.check() == true){
                Project42.setCheck(0);
                try {
                TimeUnit.SECONDS.sleep(1);
                }
                catch (Exception e) {
                    System.out.println("Sumthin weird happened here.");
                }

                System.out.println("A west-bound car is driving on the bridge.");

                try {
                TimeUnit.SECONDS.sleep(3);
                }
                catch (Exception e) {
                    System.out.println("Sumthin weird happened here.");
                }
                System.out.println("The west-bound car has crossed the bridge. West-bound cars remaining: "+(cars-1));
                cars--;
                Project42.setCheck(1);
                try {
                TimeUnit.SECONDS.sleep(1);
                }
                catch (Exception e) {
                    System.out.println("Sumthin weird happened here.");
                }
        }
    }
        System.out.println("All westbound cars crossed the bridge!");
    }
}

东行：

package project4.pkg2;

import java.util.concurrent.TimeUnit;

class EastBound implements Runnable {

    int cars = Project42.ebCars;

    EastBound(int cars){
        super();
        this.cars = cars;
    }

    @Override
    public void run() {
        //System.out.println(cars + " <- cars");
        while (cars > 0){
            if (Project42.check() == true){
                Project42.setCheck(0);
                System.out.println("An east-bound car is driving on the bridge.");
                try {
                TimeUnit.SECONDS.sleep(3);
                }
                catch (Exception e) {
                    System.out.println("Sumthin weird happened here.");
                }
                System.out.println("The east-bound car has crossed the bridge. East-bound cars remaining: "+(cars-1));
                cars--;
                Project42.setCheck(1);
                try {
                TimeUnit.SECONDS.sleep(1);
                }
                catch (Exception e) {
                    System.out.println("Sumthin weird happened here.");
                }
        }
        }
        System.out.println("All eastbound cars crossed the bridge!");
    }
}

packageproject4.pkg2；
导入java.util.concurrent.TimeUnit；
类东行实现可运行{
int cars=项目42.ebCars；
东行（国际车）{
超级（）；
这个。汽车=汽车；
}
@凌驾
公开募捐{
//System.out.println（cars+“您可以学习Java线程同步的概念。它可以帮助您使用多个线程共享同一资源。
如果两个线程正在访问同一资源（例如，读取/写入check
变量），则必须同步对该资源的访问
在这种情况下，您必须将check（）
和getCheck（）
标记为synchronized
以及同步，在运行方法中需要另一个while循环。运行方法可以在汽车仍然非零时到达终点。
使check
易失性（或使用AtomicBoolean
）。顺便问一下……为什么东行和西行需要两个类定义？一个类不能有两个实例吗？@BasilBourque我的任务规定“一个线程应该模拟西行车辆，另一个线程应该模拟东行车辆。”“@DontJudgeMe但如果行为相同，则不需要实现一对类。一个类、两个实例、两个线程。新流量（“西行”）
&新流量（“东行”）
没有理由说每个线程都需要有自己的类。每个线程都需要有自己的可运行的实例，但它们都可以是同一个类的实例。就像@BasilBourque所说的，您可能需要某种方式（例如一个参数或多个参数传递给构造函数）告诉每条线它的车应该朝哪个方向走。添加答案，而不是链接