java - 奇偶序列java 2线程

Question

我正在尝试编写一个具有两个 Java 线程的程序。一个打印奇数，另一个打印偶数。输出应该是按顺序的。我的代码无法正常工作。请更正并告诉我错误是什么。

public class App {

  public static void main(String[] args) {
    ThrdO to=new ThrdO();
    Thread t1=new Thread(to);

    ThredE te=new ThredE();
    Thread t2=new Thread(te);
    t1.start();


    t2.start();
 }

}

public class ThrdO implements Runnable{

  PrintCl pcl =new PrintCl();

  @Override
  public void run() {
    for(int i=0;i<10;i+=2)
    pcl.Even(i);    
  }
}


public class ThredE implements Runnable {

    PrintCl pcl =new PrintCl();

    @Override
    public void run() {
      for(int i=1;i<10;i+=2)
        try {
          pcl.odd(i);
        } catch (InterruptedException e) {
          // TODO Auto-generated catch block
          e.printStackTrace();
        }   
     }

public class PrintCl {
    public void Even(int n) {
      synchronized (this) {
        System.out.println(n);
        this.notifyAll();
        try {
            this.wait();
        } catch (InterruptedException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
      }         
    }

    public void odd(int n) throws InterruptedException {

        synchronized (this) {
          System.out.println(n);
          this.notifyAll();
          this.wait();  
        }
    }
}

获取输出

0 ,1

Answer 1

这是实现您想要的目标的一种更简洁的方法，代码中不会出现丑陋的 sleep ，更不用说它会比包含 sleep 的代码运行得更快，原因显而易见。

public class App {

    public static void main(String[] args) {
        PrintCl pcl = new PrintCl();

        Thread t1 = new Thread(new ThrdEven(pcl));
        Thread t2 = new Thread(new ThrdOdd(pcl));

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

public class ThrdEven implements Runnable {

    private PrintCl pcl = null;

    public ThrdEven(PrintCl pcl) {
        this.pcl = pcl;
    }

    @Override
    public void run() {
        for (int i = 0; i < 10; i += 2) {
            pcl.Even(i);
        }
    }
}

public class ThrdOdd implements Runnable {

    private PrintCl pcl = null;

    public ThrdOdd(PrintCl pcl) {
        this.pcl = pcl;
    }

    @Override
    public void run() {
        for (int i = 1; i < 10; i += 2) {
            pcl.odd(i);
        }
    }
}

public class PrintCl {

    private final Object _lock = new Object();
    private boolean isEvenAllowed = true;

    public void Even(int n) {
        synchronized (this._lock) {
            while (!this.isEvenAllowed) {
                try {
                    this._lock.wait();
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    throw new RuntimeException(e);
                }
            }
            System.out.println(n);
            this.isEvenAllowed = false;
            this._lock.notifyAll();
        }
    }

    public void odd(int n) {
        synchronized (this._lock) {
            while (this.isEvenAllowed) {
                try {
                    this._lock.wait();
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    throw new RuntimeException(e);
                }
            }
            System.out.println(n);
            this.isEvenAllowed = true;
            this._lock.notifyAll();
        }
    }
}