使用多线程打印字母和数字

Question

我刚刚开始学习线程，并且对 it.I 非常陌生，我正在尝试打印字母和数字，在 other.I 使用标志同步它们但没有用之后。

public class Alphabets {

    public static void main(String[] args) {

              AN an= new AN(false);

              Thread t1=new Thread(new Runnable() {

                @Override
                public void run() {

                    try {

                        an.Alpha();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            });


              Thread t2= new Thread(new Runnable() {

                @Override
                public void run() {
                    try {
                        an.numbers();
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }

                }
            });


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

}

...

 class AN
    {

        boolean flag;

        AN(boolean flag)
        {
            this.flag=flag;
        }
        synchronized void Alpha() throws InterruptedException
        {
            if(flag==false)
            {
            for(char i='A'; i<='Z';i++)
            {
                System.out.println(+i);
                notifyAll();
                flag=true;
            }
            }
            else
            {
                wait();
            }

        }

        synchronized void numbers() throws InterruptedException
        {
            if(flag==true)
            {
            for(int i=1;i<=26;i++)
            {
                System.out.println(+i);
                notifyAll();
                flag=false;
            }
            }
            else
            {
                wait();
            }
        }


    }

我想要的输出是：a1b2c3d4....

我的控制台输出是：abcd...1234...

谁能指出错误，因为我无法同步这两个线程。

Answer 1

更改 class AN 以检查 while 循环中的标志。

public class AN {
  boolean flag;

  AN(boolean flag) {
    this.flag = flag;
  }

  synchronized void Alpha() throws InterruptedException {

    for(char i = 'A'; i <= 'Z'; i++) {
      while(flag == true) {
        wait();
      }
      System.out.println(i);
      notifyAll();
      flag = true;
    }
  }

  synchronized void numbers() throws InterruptedException {

    for(int i = 1; i <= 26; i++) {
      while(flag == false) {
        wait();
      }
      System.out.println(i);
      notifyAll();
      flag = false;
    }
  }

Answer 2

好吧，您想要的或多或少是流水线操作，因此线程需要知道何时允许它们工作。

因此我会使用队列来等待一个线程上的输入并等待它在另一个线程中设置。

Class 安：

import java.util.concurrent.BlockingQueue;

class AN
{

    BlockingQueue<Boolean> input;

    BlockingQueue<Boolean> output;

    AN(BlockingQueue<Boolean> input, BlockingQueue<Boolean> output)
    {

        this.input = input;
        this.output = output;
    }

    void Alpha() throws InterruptedException
    {
        for (char i = 'a'; i <= 'z'; i++) {
            input.take();
            System.out.print(i);
            output.put(Boolean.TRUE);

        }
    }

    void numbers() throws InterruptedException
    {
        for (int i = 1; i <= 26; i++) {
            input.take();
            System.out.print(i);
            output.put(Boolean.TRUE);
        }

    }

}

Class 测试（或者你的主线在哪里）：

import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;

public class Test
{

    public static void main(String[] args) throws InterruptedException
    {

        BlockingQueue<Boolean> input = new LinkedBlockingQueue<>();
        BlockingQueue<Boolean> output = new LinkedBlockingQueue<>();

        AN an1 = new AN(output, input);
        AN an2 = new AN(input, output);
        output.add(Boolean.TRUE);

        Thread t1 = new Thread(new Runnable()
        {

            @Override
            public void run()
            {
                try {
                    an1.Alpha();
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        });

        Thread t2 = new Thread(new Runnable()
        {

            @Override
            public void run()
            {
                try {
                    an2.numbers();
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }

            }
        });

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

    }
}

输出：a1b2c3d4e5f6g7h8i9j10k11l12m13n14o15p16q17r18s19t20u21v22w23x24y25z26

Answer 3

您可以通过使用 BlockingQueue 和 Object 的等待和通知方法来实现。

public class AlphaNum {
    public static void main(String[] args) throws InterruptedException {


    BlockingQueue<String> queue = new ArrayBlockingQueue<String>(10);

    AtomicBoolean flag = new AtomicBoolean(Boolean.TRUE);

    Object lock = new Object();

    Thread t1 = new Thread(new Runnable() {
        @Override
        public void run() {

            try {
                for(int i=1;i<=26;i++){
                        synchronized (lock){
                            while (flag.get()){
                                lock.wait();
                            }
                            System.out.print(i);
                            flag.set(Boolean.TRUE);
                            lock.notify();
                    }
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

        }
    });

    Thread t2 = new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                for(char c='A';c<='Z';c++){
                    synchronized (lock){
                        while (!flag.get()){
                            lock.wait();
                        }
                        System.out.print(c);
                        flag.set(Boolean.FALSE);
                        lock.notify();
                    }
                }

            } catch (InterruptedException e) {
                e.printStackTrace();
            }

        }
    });


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

    }
}

以上代码打印 a1b2c3d4.......z26

使用多线程打印字母和数字

Printing Alphabets and Numbers using multi-threading

java

multithreading

synchronization

thread-synchronization