类 Exchanger 的功能可以使2个线程之间传输数据，比生产者/消费者模式方便。

Exchanger类的结构很简单，重点就是exchange()方法。

exchange()方法是阻塞执行的，可以设置超时时间，调用不同的api即可。

exchange 的 英文意思就是交换，而对于线程而言也是这样的，就是两个线程交换信息。如果共有3个线程，且3个线程同时调用了exchange，那么就会有一个线程没有交换信息的对象，就会继续阻塞。

下面是一个例子：

共有两个类 ExchangerThread、ExchangerTest：

package com.cd.concurrent.exchanger;import java.util.concurrent.Exchanger;import java.util.concurrent.TimeUnit;import java.util.concurrent.TimeoutException;public class ExchangerThread extends Thread {    private Exchanger
     
       exchanger;    private String name;    public ExchangerThread(String name, Exchanger
      
        exchanger) {        super();        this.name = name;        this.exchanger = exchanger;    }    @Override    public void run() {        try {            //            System.out.println("线程[" + name + "]拿到消息：" + exchanger.exchange(name + "-msg"));  // 不设置超时时间，线程会一直阻塞等待            System.out.println("线程[" + name + "]拿到消息：" + exchanger.exchange(name + "-msg", 5, TimeUnit.SECONDS)); // 设置5秒的超时时间            System.out.println("线程[" + name + "]over");        } catch (InterruptedException e) {            e.printStackTrace();        } catch (TimeoutException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }}
      
     

package com.cd.concurrent.exchanger;import java.util.concurrent.Exchanger;public class ExchangerTest {    public static void main(String[] args) {        Exchanger
     
       exchanger = new Exchanger
      
       ();        ExchangerThread t1 = new ExchangerThread("t1", exchanger);        ExchangerThread t2 = new ExchangerThread("t2", exchanger);        ExchangerThread t3 = new ExchangerThread("t3", exchanger);        t1.start();        t2.start();        t3.start();    }}
      
     

运行结果：