Java并发——Exchanger

Exchanger

Exchanger的功能可以使2个线程之间传输数据,它比生产者/消费者模式使用的 wait/notify要更加方便。

exchange()阻塞的特性：

public class ThreadA extends Thread{
    private Exchanger<String> exchanger;

    public ThreadA(Exchanger<String> exchanger) {
        this.exchanger = exchanger;
    }

    @Override
    public void run() {
        try {
            System.out.println("在线程A中得到线程B的值=" + exchanger.exchange("A"));
            System.out.println("A end!");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        Exchanger<String> exchanger = new Exchanger<>();
        ThreadA a = new ThreadA(exchanger);
        a.start();
        System.out.println("main end");
    }
}

exchange()传递数据：

public class ThreadA extends Thread{
    private Exchanger<String> exchanger;

    public ThreadA(Exchanger<String> exchanger) {
        this.exchanger = exchanger;
    }

    @Override
    public void run() {
        try {
            System.out.println("在线程A中得到线程B的值=" + exchanger.exchange("A"));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

public class ThreadB extends Thread {
    private Exchanger<String> exchanger;

    public ThreadB(Exchanger<String> exchanger) {
        this.exchanger = exchanger;
    }

    @Override
    public void run() {
        try {
            System.out.println("在线程B中得到线程A的值=" + exchanger.exchange("B"));
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        Exchanger<String> exchanger = new Exchanger<>();
        ThreadA a = new ThreadA(exchanger);
        ThreadB b = new ThreadB(exchanger);
        a.start();
        b.start();
    }
}

exchange(V x, long timeout, TimeUnit unit)与超时：

当调用 exchange(Vx, long timeout, TimeUnit unit)方法后在指定的时间内没有其他线程获取数据,则出现超时异常。

public class ThreadA extends Thread{
    private Exchanger<String> exchanger;

    public ThreadA(Exchanger<String> exchanger) {
        this.exchanger = exchanger;
    }

    @Override
    public void run() {
        try {
            System.out.println("在线程A中得到线程B的值=" + exchanger.exchange("A", 5, TimeUnit.SECONDS));
            System.out.println("A end!");
        } catch (InterruptedException | TimeoutException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) {
        Exchanger<String> exchanger = new Exchanger<>();
        ThreadA a = new ThreadA(exchanger);
        a.start();
        System.out.println("main end");
    }
}