Exchanger

用于两个线程之间进行交换数据。
线程A执行到exchange(s)其阻塞住，并且把数据放置于格子1处；
线程B执行到exchange(s)同样被阻塞住，并把数据放置于格式2处，进行数据交换。然后格子往下执行。
使用场景：两个线程之间互相通信，双人游戏交换装备等

import java.util.concurrent.Exchanger;
public class T12_TestExchanger {
    static Exchanger<String> exchanger = new Exchanger<>();
    public static void main(String[] args) {
        new Thread(()->{
            String s = "T1";
            try {
                s = exchanger.exchange(s);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName() + " " + s);
        }, "t1").start();
        new Thread(()->{
            String s = "T2";
            try {
                s = exchanger.exchange(s);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName() + " " + s);
        }, "t2").start();
    }
}
执行结果：
t2 T1
t1 T2

Process finished with exit code 0