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Java并发（十六）：并发工具类——Exchanger
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Exchanger（交换者）是一个用于线程间协作的工具类。Exchanger用于进行线程间的数据交换。它提供一个同步点，在这个同步点两个线程可以交换彼此的数据。这两个线程通过exchange方法交换数据， 如果第一个线程先执行exchange方法，它会一直等待第二个线程也执行exchange，当两个线程都到达同步点时，这两个线程就可以交换数据，将本线程生产出来的数据传递给对方。
举例
class ExchangerTest {
static class Producer implements Runnable {
// 生产者、消费者交换的数据结构
private List<String> buffer;
// 步生产者和消费者的交换对象
private Exchanger<List<String>> exchanger;
Producer(List<String> buffer, Exchanger<List<String>> exchanger) {
this.buffer = buffer;
this.exchanger = exchanger;
}
@Override
public void run() {
for (int i = 1; i < 5; i++) {
for (int j = 1; j <= 3; j++) {
System.out.println("生产者装入" + i + "--" + j);
buffer.add("buffer：" + i + "--" + j);
}
System.out.println("生产者装满，等待与消费者交换...");
try {
exchanger.exchange(buffer);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.err.println("生产者 " + i + ":" + buffer);
}
}
}
static class Consumer implements Runnable {
private List<String> buffer;
private final Exchanger<List<String>> exchanger;
public Consumer(List<String> buffer, Exchanger<List<String>> exchanger) {
this.buffer = buffer;
this.exchanger = exchanger;
}
@Override
public void run() {
for (int i = 1; i < 5; i++) {
// 调用exchange()与消费者进行数据交换
try {
buffer = exchanger.exchange(buffer);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("消费者第" + i + "次提取");
for (int j = 1; j <= 3; j++) {
System.out.println("消费者 : " + buffer.get(0));
buffer.remove(0);
}
}
}
}
public static void main(String[] args) {
List<String> buffer1 = new ArrayList<String>();
List<String> buffer2 = new ArrayList<String>();
Exchanger<List<String>> exchanger = new Exchanger<List<String>>();
Thread producerThread = new Thread(new Producer(buffer1, exchanger));
Thread consumerThread = new Thread(new Consumer(buffer2, exchanger));
producerThread.start();
consumerThread.start();
}
}
并发工具类（四）两个线程进行数据交换的Exchanger
【死磕Java并发】—–J.U.C之并发工具类：Exchanger
