作用

用来交换两个线程的数据。

示例

public class ExchangerDemo {    static Exchanger<String> exchanger = new Exchanger<>();    static class Thread1 extends Thread {        @Override        public void run() {            try {                sleep(3000);                String str = exchanger.exchange("a");                System.out.println(Thread.currentThread().getName() + "-" + str);            } catch (InterruptedException e) {                e.printStackTrace();            }        }    }    static class Thread2 extends Thread {        @Override        public void run() {            try {                String str = exchanger.exchange("b");                System.out.println(Thread.currentThread().getName() + "-" + str);            } catch (InterruptedException e) {                e.printStackTrace();            }        }    }    public static void main(String[] args) {        Thread1 thread1 = new Thread1();        Thread2 thread2 = new Thread2();        thread1.start();        thread2.start();    }}

运行结果如下：

首先，会经过三秒后，才输出结果，说明两个线程没交换之前是阻塞的。输出结果可以看出，两个线程的字符串交换了。