Exchanger
Exchanger
public class ExchangeTest {
public static void main(String[] args) {
ExecutorService service = Executors.newCachedThreadPool();
final Exchanger exchanger = new Exchanger();
service.execute(new Runnable() {
@Override
public void run() {
try {
String data1 = "零食";
System.out.println("线程" + Thread.currentThread().getName() +
"正在把数据 " + data1 + " 换出去");
Thread.sleep((long) Math.random() * 10000);
String data2 = (String) exchanger.exchange(data1);
System.out.println("线程 " + Thread.currentThread().getName() +
"换回的数据为 " + data2);
} catch (Exception e) {
e.printStackTrace();
}
}
});
service.execute(new Runnable() {
@Override
public void run() {
try {
String data1 = "钱";
System.out.println("线程" + Thread.currentThread().getName() +
"正在把数据 " + data1 + " 交换出去");
Thread.sleep((long)(Math.random() * 10000));
String data2 = (String) exchanger.exchange(data1);
System.out.println("线程 " + Thread.currentThread().getName() +
"交换回来的数据是: " + data2);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
}
最后结果为：
线程pool-1-thread-1正在把数据 零食 换出去
线程pool-1-thread-2正在把数据 钱 交换出去
线程 pool-1-thread-1换回的数据为 钱
线程 pool-1-thread-2交换回来的数据是: 零食
Asynchronous（异步）
Timeouts
任何 future.get()调用都会阻塞，然后等待直到 callable 中止。在最糟糕的情况下，一个 callable 持续运行——因此使你的程序将没有响应。我们可以简单的传入一个时长来避免这种情况。
ExecutorService executor = Executors.newFixedThreadPool(1);
Future<Integer> future = executor.submit(() -> {
try {
TimeUnit.SECONDS.sleep(2);
return 123;
}
catch (InterruptedException e) {
throw new IllegalStateException("task interrupted", e);
}
});
future.get(1, TimeUnit.SECONDS);
运行上面的代码将会产生一个 TimeoutException:
Exception in thread "main" java.util.concurrent.TimeoutException
at java.util.concurrent.FutureTask.get(FutureTask.java:205)