多线程-为所有变量请求一次输入（Java）

下面是多线程函数的代码和输出，其中有一个计数器和加法、减法、乘法和除法函数。我正在使用Eclipse

每个数学函数有4个线程：

public class Maths {

    public static void main(String args[]){

        CalculationThread T1 = new CalculationThread("Addition");
        T1.start();

        CalculationThread T2 = new CalculationThread("Subtraction");
        T2.start();

        CalculationThread T3 = new CalculationThread("Multiplication");
        T3.start();

        CalculationThread T4 = new CalculationThread("Division");
        T4.start();
    }
}

class CalculationThread extends Thread{
    private Thread t;
    private String maths;
    private int count = 0;
    private int resultplus, resultminus, resulttimes, resultdivide = 0;

    CalculationThread(String answer){
        maths = answer;
    }

    public void start(){
        System.out.println("Starting calculation of " + maths + "\n");
        if(t == null){
            t = new Thread (this, maths);
            t.start();
        }
    }

这里是函数发生的地方，它将使用计数器作为2个数字来执行一个等式

    public void run(){
        try {
            for (int x=0; x<=3 ; x++){

                if(maths == "Addition"){
                System.out.println("Calculating: " + maths + " of " + count + 
                        " + "+ count + " = " + resultplus + "\n");
                Thread.sleep(3000);
                count++;
                resultplus = count + count;
                }

                else if(maths == "Subtraction"){
                    System.out.println("Calculating: " + maths + " of " + count + 
                            " - "+ count + " = " + resultminus + "\n");
                    Thread.sleep(3000);
                    count++;
                    resultminus = count - count;
                }

                else if(maths == "Multiplication"){
                    System.out.println("Calculating: " + maths + " of " + count + 
                            " * "+ count + " = " + resulttimes + "\n");
                    Thread.sleep(3000);
                    count++;
                    resulttimes = count * count;
                }

                else if(maths == "Division"){
                    System.out.println("Calculating: " + maths + " of " + count + 
                            " / "+ count + " = " + resultdivide + "\n");
                    Thread.sleep(3000);
                    count++;
                    resultdivide = count / count;
                }

            }

        }
            catch (InterruptedException e){
                System.out.println("Math function failed");
            }
                if(maths == "Addition"){
                System.out.println("Addition completed.");
                }
                else if(maths == "Subtraction"){
                    System.out.println("Subtraction completed.");
                }
                else if(maths == "Multiplication"){
                    System.out.println("Multiplication completed.");
                }
                else if(maths == "Division"){
                    System.out.println("Division completed.");
                }
    }
}

---

上面的代码可以同时完成所有4个函数，但是每当我尝试包含一个JOptionPane以供用户输入而不是一个自动计数器时，4个线程中的每一个都会一次请求。因此，如果函数正在等待我输入2个数字，则它不算作多线程。如何以及以何种方式包含一个只需要用户在开始时输入的用户输入，以便所有函数都可以使用这两个变量。

我不确定是否正确理解它

如果您只想阻塞计算线程并等待初始用户输入，则可以使用

信号灯

等待用户输入的UI线程显示对话框，并通过设置许可/线程数释放等待的计算线程

下面是一个这样的示例（它还使用了更面向对象的方法）。为简单起见，我跳过了乘法和除法任务

import java.util.concurrent.Semaphore;

import javax.swing.JOptionPane;

public class MathSample {

    // because updated / read from different threads mark as volatile 
    private volatile int a, b;

    // semaphore with no initial permits i.e.
    // the calculations will wait until permits are available.
    private Semaphore available = new Semaphore(0);

    private abstract class Task implements Runnable {

        public abstract void doCalculation();

        public abstract String getName();

        @Override
        public void run() {
            try {
                // wait until a permit becomes available
                available.acquire();
                // not sure what should happen here
                // wait again for user input? 
                for (int x = 0; x < 50; ++x) {
                    a = a + x;
                    doCalculation();
                }

            } catch (InterruptedException e) {
                Thread.currentThread().interrupt();
            }

            System.out.println(String.format("Task %s completed.", getName()));
        }

    }


    private  class AdditionTask extends Task {

        public void doCalculation() {
            System.out.println(String.format("Calculating: Addition of + %d + %d = %d", a, b, a+b));
        }
        public String getName() {
            return "Addition";
        }
    }

    private  class SubstractionTask extends Task {
        public void doCalculation() {
            System.out.println(String.format("Calculating: Substraction of + %d - %d = %d", a, b, a-b));
        }

        public String getName() {
            return "Substraction";
        }
    }



    private void run() {
        new Thread(new AdditionTask()).start();
        new Thread(new SubstractionTask()).start();


        a = Integer.parseInt(JOptionPane.showInputDialog("First value"));
        b = Integer.parseInt(JOptionPane.showInputDialog("Second value"));
        available.release(2); // let the 2 calculation threads run

    }


    public static void main(String ...args) {
        new MathSample().run();

    }
}

---

您可以参考以下代码。 根据我对你问题的理解，也许它会适合你的需要。我还根据装满鳗鱼的气垫船的建议，对代码应用了

.equals（）

import javax.swing.JOptionPane;

public class Maths {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String num1 = JOptionPane.showInputDialog("Num1: ");
        String num2 = JOptionPane.showInputDialog("Num2: ");
        int num11 = Integer.parseInt(num1);
        int num22 = Integer.parseInt(num2);

        calculationThread T1 = new calculationThread("Addition");
        T1.getNumber(num11, num22);
        T1.start();

        calculationThread T2 = new calculationThread("Subtraction");
        T2.getNumber(num11, num22);
        T2.start();

        calculationThread T3 = new calculationThread("Multiplication");
        T3.getNumber(num11, num22);
        T3.start();

        calculationThread T4 = new calculationThread("Division");
        T4.getNumber(num11, num22);
        T4.start();
    }
}

class calculationThread extends Thread{
    private Thread t;
    private String maths;
    private int a;
    private int b;
    private int resultplus = 0;
    private int resultminus = 0;
    private int resulttimes = 0;
    private int resultdivide = 0;

    public void getNumber(int num1, int num2){
        a = num1;
        b = num2;
    }

    calculationThread(String answer){
        maths = answer;
    }

    public void start(){
        System.out.println("Starting calculation of " + maths + "\n");
        if(t == null){
            t = new Thread(this, maths);
            t.start();
        }
    }

    public void run(){
        try {
            for (int x=0; x<=3 ; x++){
                if(maths.equals("Addition")){
                System.out.println("Calculating: " + maths + " of " + a + 
                        " + "+ b + " = " + resultplus + "\n");
                Thread.sleep(3000);
                resultplus = a + b;
                }
                else if(maths.equals("Subtraction")){
                    System.out.println("Calculating: " + maths + " of " + a + 
                            " - "+ b + " = " + resultminus + "\n");
                    Thread.sleep(3000);
                    resultminus = a - b;
                }
                else if(maths.equals("Multiplication")){
                    System.out.println("Calculating: " + maths + " of " + a + 
                            " * "+ b + " = " + resulttimes + "\n");
                    Thread.sleep(3000);
                    resulttimes = a * b;
                }   
                else if(maths.equals("Division")){
                    System.out.println("Calculating: " + maths + " of " + a + 
                            " / "+ b + " = " + resultdivide + "\n");
                    Thread.sleep(3000);
                    resultdivide = a / b;
                }   
            }   
        }
        catch (InterruptedException e){
            System.out.println("Math function failed");
        }
        finally{
            if(maths.equals("Addition")){
                System.out.println("Addition completed.");
            }
            else if(maths.equals("Subtraction")){
                System.out.println("Subtraction completed.");
            }
            else if(maths.equals("Multiplication")){
                System.out.println("Multiplication completed.");
            }
            else if(maths.equals("Division")){
                System.out.println("Division completed.");
            }           
        }
    }
}

import javax.swing.JOptionPane；
公共课数学{
公共静态void main（字符串[]args）{
//TODO自动生成的方法存根
字符串num1=JOptionPane.showInputDialog（“num1:”）；
字符串num2=JOptionPane.showInputDialog（“num2:”）；
int num11=整数.parseInt（num1）；
int num22=整数.parseInt（num2）；
calculationThread T1=新的calculationThread（“加法”）；
T1.getNumber（num11，num22）；
T1.start（）；
calculationThread T2=新的calculationThread（“减法”）；
T2.getNumber（num11，num22）；
T2.start（）；
calculationThread T3=新的calculationThread（“乘法”）；
T3.获取编号（num11，num22）；
T3.start（）；
calculationThread T4=新的calculationThread（“除法”）；
T4.获取编号（num11，num22）；
T4.开始（）；
}
}
类calculationThread扩展线程{
私有线程t；
私人字符串数学；
私人INTA；
私人INTB；
私有int resultplus=0；
私有int resultminus=0；
私有int resulttimes=0；
私有int resultdivide=0；
公共无效获取编号（整数num1，整数num2）{
a=num1；
b=num2；
}
计算线程（字符串应答）{
数学=答案；
}
公开作废开始（）{
System.out.println（“开始计算“+数学+”\n”）；
如果（t==null）{
t=新线程（这是数学）；
t、 start（）；
}
}
公开募捐{
试一试{
对于（int x=0；xSide问题，关于：
if（math==“Addition”）{
：不要使用
=
或
！=
比较字符串。使用
等于（…）
或
相等信号格（…）
方法。请理解
==
检查两个对象引用是否相同，这不是您感兴趣的。另一方面，这些方法检查两个字符串是否具有相同顺序的相同字符，这在这里很重要。另一个次要问题：如中所述，您应该编写一个在extends
Thread
，重写
run（）
方法，创建类的实例，并调用
start（）
，或者编写实现
Runnable
的类，创建类的实例，将实例传递给
Thread
的构造函数，然后调用
start（）
线程上的
实例。
class Calculation implements Runnable {
   ...
   @override 
   public void run() {
      // the name you passed to the thread is your math 
      // lets get it from the currently running thread where it is stored.         
      final String math = Thread.currentThread().getName();
      ...
   }

}

// somewhere else 
new Thread(new CalculationThread, math).start(); 

import javax.swing.JOptionPane;

public class Maths {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        String num1 = JOptionPane.showInputDialog("Num1: ");
        String num2 = JOptionPane.showInputDialog("Num2: ");
        int num11 = Integer.parseInt(num1);
        int num22 = Integer.parseInt(num2);

        calculationThread T1 = new calculationThread("Addition");
        T1.getNumber(num11, num22);
        T1.start();

        calculationThread T2 = new calculationThread("Subtraction");
        T2.getNumber(num11, num22);
        T2.start();

        calculationThread T3 = new calculationThread("Multiplication");
        T3.getNumber(num11, num22);
        T3.start();

        calculationThread T4 = new calculationThread("Division");
        T4.getNumber(num11, num22);
        T4.start();
    }
}

class calculationThread extends Thread{
    private Thread t;
    private String maths;
    private int a;
    private int b;
    private int resultplus = 0;
    private int resultminus = 0;
    private int resulttimes = 0;
    private int resultdivide = 0;

    public void getNumber(int num1, int num2){
        a = num1;
        b = num2;
    }

    calculationThread(String answer){
        maths = answer;
    }

    public void start(){
        System.out.println("Starting calculation of " + maths + "\n");
        if(t == null){
            t = new Thread(this, maths);
            t.start();
        }
    }

    public void run(){
        try {
            for (int x=0; x<=3 ; x++){
                if(maths.equals("Addition")){
                System.out.println("Calculating: " + maths + " of " + a + 
                        " + "+ b + " = " + resultplus + "\n");
                Thread.sleep(3000);
                resultplus = a + b;
                }
                else if(maths.equals("Subtraction")){
                    System.out.println("Calculating: " + maths + " of " + a + 
                            " - "+ b + " = " + resultminus + "\n");
                    Thread.sleep(3000);
                    resultminus = a - b;
                }
                else if(maths.equals("Multiplication")){
                    System.out.println("Calculating: " + maths + " of " + a + 
                            " * "+ b + " = " + resulttimes + "\n");
                    Thread.sleep(3000);
                    resulttimes = a * b;
                }   
                else if(maths.equals("Division")){
                    System.out.println("Calculating: " + maths + " of " + a + 
                            " / "+ b + " = " + resultdivide + "\n");
                    Thread.sleep(3000);
                    resultdivide = a / b;
                }   
            }   
        }
        catch (InterruptedException e){
            System.out.println("Math function failed");
        }
        finally{
            if(maths.equals("Addition")){
                System.out.println("Addition completed.");
            }
            else if(maths.equals("Subtraction")){
                System.out.println("Subtraction completed.");
            }
            else if(maths.equals("Multiplication")){
                System.out.println("Multiplication completed.");
            }
            else if(maths.equals("Division")){
                System.out.println("Division completed.");
            }           
        }
    }
}