调用exchange方法，第一个调用的线程会进入bloking状态，等到下一个线程调用 会完成交换
abcde 如果5个线程都调用了exchange方法 最终是 ab交换 cd交换 e线程一直阻塞等待中。。。
还有一个重载的方法 V exchange(V v, long timeout, TimeUnit unit) 见名知意~

import java.util.concurrent.Exchanger;
import java.util.concurrent.TimeUnit;

/**
 * @author: zhouwei
 * @version: v1.0
 * @description: com.service.callgraphy.thread_learn
 * @date:2021-01-25
 */
public class ExchangerL {
   static Exchanger exchanger= new Exchanger();
    public static void main(String[] args) {
        new Thread(()->{
            System.out.println(Thread.currentThread().getName()+"start 100");
            try {
                TimeUnit.SECONDS.sleep(1);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            try {
               int a =(int) exchanger.exchange(100);
                System.out.println(Thread.currentThread().getName()+"交换拿到的值"+a);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }).start();

        new Thread(()->{
            System.out.println(Thread.currentThread().getName()+"start  100000");
            try {
                TimeUnit.SECONDS.sleep(5);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            try {
               int a =(int) exchanger.exchange(100000);
                System.out.println(Thread.currentThread().getName()+"交换拿到的值"+a);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }).start();
    }
}

打印结果：

Thread-0start 100
Thread-1start  100000
Thread-1交换拿到的值100
Thread-0交换拿到的值100000