Java多线程开发工具之CompletableFuture的应用详解

/**
     * 女神化完妆之后，还需要一小会选衣服，不过分吧。
     * 也就是说我们现在有2个异步任务，第一个是化妆，第二个是选衣服。
     * 选衣服要在化妆完成之后进行，这两个任务是串行
     */
    public static void main(String[] args) {
        // 线程池我前面的文章聊过，怎么配置可以去了解一下
       ThreadPoolExecutor threadPool= new ThreadPoolExecutor(2, 10, 10, TimeUnit.SECONDS,
                new LinkedBlockingDeque<>(10), Executors.defaultThreadFactory(), new ThreadPoolExecutor.AbortPolicy());
        //任务1
        CompletableFuture<String> makeUpFuture = CompletableFuture.supplyAsync(() -> {
            System.out.println(Thread.currentThread().getName() + "-女神，开始化妆了");
            try {
                // 化妆的时间
                TimeUnit.SECONDS.sleep(5);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return "化妆完毕了。";
        }, threadPool);
       //任务2，makeUp是调用方，意思是makeUpFuture执行完后再执行
        CompletableFuture<String> dressFuture = makeUpFuture.thenApply((result) -> {
            System.out.println(Thread.currentThread().getName() + "-女神" + result + "我开始选衣服啦，好了叫你！");
            try {
                // 换衣服的时间
                TimeUnit.SECONDS.sleep(5);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return result + "衣服也选好了,走出去玩吧！";
        });
        dressFuture.thenAccept((result) -> {
            System.out.println(Thread.currentThread().getName() + "-" + result);
        });
    }

ThreadPoolExecutor threadPool = new ThreadPoolExecutor(2, 10, 10, TimeUnit.SECONDS,
                new LinkedBlockingDeque<>(10), Executors.defaultThreadFactory(), new ThreadPoolExecutor.AbortPolicy());
​
        CompletableFuture.runAsync(() -> {
            System.out.println(Thread.currentThread().getName());
            int i = 10 / 2;
            System.out.println("运行的结果是：" + i);
        }, threadPool);
​
        CompletableFuture future = CompletableFuture.supplyAsync(() -> {
                    try {
                        Thread.sleep(2);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                    return "Hello World";
                }, threadPool);
        System.out.println(future.get());

ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 10, 10, TimeUnit.SECONDS,
                new LinkedBlockingDeque<>(10), Executors.defaultThreadFactory(), new ThreadPoolExecutor.AbortPolicy());
        CompletableFuture<String> futureA = CompletableFuture.supplyAsync(() ->
        {
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("执行任务A");
            return "任务A";
        }, executor);
        CompletableFuture<String> futureB = CompletableFuture.supplyAsync(() -> {
            System.out.println("执行任务B");
            return "任务B";
        }, executor);
        CompletableFuture<String> futurec = futureB.thenApply((b) -> {
            System.out.println("执行任务C");
            System.out.println("参数：" + b);
            return "a";
        });
        System.out.println(futurec.get());

ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 10, 10, TimeUnit.SECONDS,
                new LinkedBlockingDeque<>(10), Executors.defaultThreadFactory(), new ThreadPoolExecutor.AbortPolicy());
        CompletableFuture futureA = CompletableFuture.supplyAsync(() -> "Hello", executor);
        CompletableFuture futureB = futureA.thenApply((a) -> a + " World");
        CompletableFuture futureC = futureB.thenApply((b) -> b);
        System.out.println(futureC.join());

ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 10, 10, TimeUnit.SECONDS,
                new LinkedBlockingDeque<>(10), Executors.defaultThreadFactory(), new ThreadPoolExecutor.AbortPolicy());
        CompletableFuture<Integer> futureA = CompletableFuture.supplyAsync(() -> 10, executor);
        CompletableFuture<Integer> futureB = CompletableFuture.supplyAsync(() -> 20, executor);
        CompletableFuture futureC = futureA.thenCombineAsync(futureB, (r1, r2) -> {
            System.out.println("r1的值为：" + r1 + ":r2的值为:" + r2);
            return r1 + r2;
        });
        System.out.println(futureC.get());

ThreadPoolExecutor executor = new ThreadPoolExecutor(2, 10, 10, TimeUnit.SECONDS,
                new LinkedBlockingDeque<>(10), Executors.defaultThreadFactory(), new ThreadPoolExecutor.AbortPolicy());
        System.out.println("start...");
        CompletableFuture<String> future1 = CompletableFuture.supplyAsync(() -> {
            System.out.println("查询商品信息1");
            return "future1";
        }, executor);
​
        CompletableFuture<String> future2 = CompletableFuture.supplyAsync(() -> {
            System.out.println("查询商品信息2");
            return "future2";
        }, executor);
​
        CompletableFuture<String> future3 = CompletableFuture.supplyAsync(() -> {
            System.out.println("查询商品信息3");
            return "future3";
        }, executor);
​
        final CompletableFuture<Void> voidCompletableFuture = CompletableFuture.allOf(future1, future2, future3);
        voidCompletableFuture.get();
        System.out.println("end...future1的结果：" + future1.get() + ",future2的结果：" + future2.get() + ",future3的结果：" + future3.get());