JAVA获取线程执行结果的几种方式

public class FetchAdTask implements Callable<Ad> {
    @Override
    public Ad call() throws Exception {
        System.out.println("fetch task");
        sleep(1000L);
        return null;
    }
}

CompletableFuture.get();

f.get(timeLeft, TimeUnit.NANOSECONDS);

executor.invokeAll(tasks, time, unit);   

CompletableFuture<Integer> task3 = CompletableFuture.supplyAsync(() -> {
        System.out.println("任务3, 线程名字" + Thread.currentThread().getName());
        try {
            sleep(3000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return 3;
    });
    CompletableFuture.allOf(task1, task2, task3, task4);
    System.out.println("end: " + new Date());
    task1.get();

CompletionService.take();

private static final long TIME_BUDGET = 100L;
private static final Ad DEFAULT_AD = new Ad();
private final ExecutorService executor = new ThreadPoolExecutor(Runtime.getRuntime().availableProcessors() + 1,
        Runtime.getRuntime().availableProcessors() + 1, 0L,
        TimeUnit.MILLISECONDS, new LinkedBlockingQueue(1000));
public static void main(String[] args) {
    try {
        Test616LimitedTimeTask task = new Test616LimitedTimeTask();
        task.test();
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
}
/**
 * 测试超时取消
 *
 * @throws InterruptedException
 */
void test() throws InterruptedException {
    Ad ad = null;
    long endNanos = System.nanoTime() + TIME_BUDGET;
    Future<Ad> f = executor.submit(new FetchAdTask());
    try {
        long timeLeft = endNanos - System.nanoTime();
        // 增加参数 超时时间和超时时间的单位
        ad = f.get(timeLeft, TimeUnit.NANOSECONDS);
    } catch (ExecutionException e) {
        ad = DEFAULT_AD;
    } catch (TimeoutException e) {
        // 超时，取消任务
        ad = DEFAULT_AD;
        System.out.println("超时取消");
        f.cancel(true);
    }
}