java - 多线程，以便不断从集合 int 中减去或添加数字

Question

我想让 3 个线程同时执行，一个用于添加总计，一个用于从总计中减去，一个用于检查总计。减去或添加的金额由用户通过控制台输入。

到目前为止我已经:

import java.util.Scanner;

public class Calc implements Runnable {

public int add;
public int remove;
public static int Total;

static Scanner s = new Scanner(System.in);

public static int add(int a){
    System.out.println("How much was added? \n");
    a = s.nextInt();
    Total = Total + a;
    return Total;
}


public int remove(int b){
    System.out.println("How much was removed? \n");
    b = s.nextInt();
    return Total = Total - b;
}

public void check(){
    System.out.println("Would you like to know how much is left? \n");
    if(s.nextLine().equals("Yes"))
        System.out.println(Total);

}


@Override
public void run() {
    // TODO Auto-generated method stub

}

}


public class Calculate{
public static void main(String[] args){

    Thread t1 = new Thread(new Calc("add"));
    Thread t2 = new Thread(new Calc("remove"));
    Thread t3 = new Thread(new Calc("check"));

    t1.start();
    t2.start();
    t3.start();
}
}

有人能指出我正确的方向吗？

Answer 1

我不明白这有什么用处，但对于您的特殊需求，您“可能”可以使用类似的东西:

import java.util.Scanner;

public class Calc {

    public static void main(String[] args) {

        Thread t1 = new Thread(new Runnable() {

            @Override
            public void run() {
                while (true) { // change condition to whatever
                    add();
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
        });
        Thread t2 = new Thread(new Runnable() {

            @Override
            public void run() {
                while (true) { // change condition to whatever
                    remove();
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
        });
        Thread t3 = new Thread(new Runnable() {

            @Override
            public void run() {
                while (true) { // change condition to whatever
                    check();
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
        });

        t1.start();
        t2.start();
        t3.start();

    }

    static int total = 0;

    static Scanner s = new Scanner(System.in);

    static synchronized int add() {
        System.out.println("How much was added?");
        int a = s.nextInt();
        total = total + a;
        return total;
    }

    static synchronized int remove() {
        System.out.println("How much was removed?");
        int b = s.nextInt();
        return total = total - b;
    }

    static synchronized void check() {
        System.out.println("Would you like to know how much is left?");
        String str = s.next();
        if (str.equals("Yes"))
            System.out.println(total);

    }

}

请注意，您不需要使用线程来完成您想要做的事情。