java8的CompletableFuture使用实例

acceptEither(取2个future中最先返回的,无返回值)

/**
     * 取其中返回最快的一个
     * 当任意一个CompletionStage 完成的时候，action 这个消费者就会被执行。这个方法返回 CompletableFuture
     */
    @Test
    public void testAcceptEither() throws ExecutionException, InterruptedException {
        CompletableFuture f1 = CompletableFuture.supplyAsync(() -> {
            try {
                System.out.println("f1 start to sleep at:"+System.currentTimeMillis());
                TimeUnit.SECONDS.sleep(3);
                System.out.println("f1 stop sleep at:"+System.currentTimeMillis());
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return "zero";
        }, executor);
        CompletableFuture f2 = CompletableFuture.supplyAsync(() -> {
            try {
                System.out.println("f2 start to sleep at:"+System.currentTimeMillis());
                TimeUnit.SECONDS.sleep(5);
                System.out.println("f2 stop sleep at:"+System.currentTimeMillis());
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return "hello";
        }, executor);

        CompletableFuture reslutFuture = f1.acceptEither(f2,r -> {
            System.out.println("quicker result:"+r);
        });
        reslutFuture.get(); //should be null , wait for complete

    }

allOf(等待所有future返回)

    /**
     * 等待多个future返回
     */
    @Test
    public void testAllOf() throws InterruptedException {
        List> futures = IntStream.range(1,10)
                .mapToObj(i ->
                        longCost(i)).collect(Collectors.toList());
        final CompletableFuture allCompleted = CompletableFuture.allOf(futures.toArray(new CompletableFuture[]{}));
        allCompleted.thenRun(() -> {
            futures.stream().forEach(future -> {
                try {
                    System.out.println("get future at:"+System.currentTimeMillis()+", result:"+future.get());
                } catch (InterruptedException | ExecutionException e) {
                    e.printStackTrace();
                }
            });

        });
        Thread.sleep(100000); //wait
    }

anyOf(取多个future当中最快的一个返回)

/**
     * 等待多个future当中最快的一个返回
     * @throws InterruptedException
     */
    @Test
    public void testAnyOf() throws InterruptedException {
        List> futures = IntStream.range(1,10)
                .mapToObj(i ->
                        longCost(i)).collect(Collectors.toList());
        final CompletableFuture