線程之間Exchanger通信簡例

import java.util.concurrent.Exchanger;

public class Test3
{
    public static void main(String[] args){
        Exchanger<String> exchange = new Exchanger<String>();
        new Thread(new A(exchange)).start();
        new Thread(new B(exchange)).start();
    }

}

class A  implements Runnable {

    private Exchanger<String> exchange ;

    public A(Exchanger<String> exchange)
    {
        super();
        this.exchange = exchange;
    }

    public void run()
    {
        String s1 = "原來是A的s1";
        String s2 = "原來是A的s2";

        try
        {
            System.out.println("A第一次交換start");

            s1 = exchange.exchange(s1);

            System.out.println("A第二次交換start");
            s2 = exchange.exchange(s2);
            System.out.println("A交換結束,A中s1: "+s1+",A中s2: "+s2);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

}

class B implements Runnable{
    private Exchanger<String> exchange ;

    public B(Exchanger<String> exchange)
    {
        super();
        this.exchange = exchange;
    }

    public void run()
    {
        String s3 = "原來是B的s3";
        String s4 = "原來是B的s4";
        try
        {
            System.out.println("B第一次交換start");
            Thread.sleep(3000);
            s3 = exchange.exchange(s3);
            Thread.sleep(3000);
            System.out.println("B第二次交換start");
            s4 = exchange.exchange(s4);
            System.out.println("B交換結束,B中s3: "+s3+",B中s4: "+s4);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

}

A第一次交換start
B第一次交換start
//等待-每個線程的Exchanger會等待另一個，交換完後往後執行
A第二次交換start
//等待
B第二次交換start
B交換結束,B中s3: 原來是A的s1,B中s4: 原來是A的s2
A交換結束,A中s1: 原來是B的s3,A中s2: 原來是B的s4