J.U.C——Future

class Task implements Callable<Integer> {
    @Override
    public Integer call() throws Exception {
        System.out.println("子线程正在计算1-100的结果");
        Thread.sleep(100);
        int sum = 0;
        for (int i = 0; i < 100; i++) {
            sum += i;
        }
        return sum;
    }
}
public class FutureTaskDemo {
    public static void main(String[] args) {
        Task task = new Task();
        FutureTask<Integer> integerFutureTask = new FutureTask<>(task);
        ExecutorService service = Executors.newCachedThreadPool();
        service.submit(integerFutureTask);
        try {
            System.out.println("1-100运行结果：" + integerFutureTask.get());
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }
}

转成lamb

public class OneFutureLambda {
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        ExecutorService service = Executors.newFixedThreadPool(10);
        Future<Integer> future = service.submit(new Callable<Integer>() {
            @Override
            public Integer call() throws Exception {
                Integer sum = 0;
                for (int i = 1; i < 100; i++) {
                    sum += i;
                }
                return sum;
            }
        });
        try {
            System.out.println(future.get());
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
        service.shutdown();
    }
}

等价于

  Future<Integer> future = service.submit(() -> {
            Integer sum = 0;
            for (int i = 1; i < 100; i++) {
                sum += i;
            }
            return sum;
        });