相关疑难解决方法(0)

最近,我已经看到Promise的概念在AngularJS和JQuery中实现.

我已经在下面的代码中看到了Java中的Futures的实现,但是这需要在语言/平台中存在线程池的概念.但是,Javascript中没有这样的线程概念.如何实现Javascript中的Promise？

public class Futures1 {

    private static final ExecutorService pool = Executors
            .newFixedThreadPool(10);

    public static void main(String[] args) {

        Future<String> contentsFuture = null;
        try {
            contentsFuture = startDownloading(new URL("http://www.example.com"));
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
        // other computation
        try {
            final String contents = contentsFuture.get();
        } catch (InterruptedException | ExecutionException e) {
            e.printStackTrace();
        }

    }

    public static Future<String> startDownloading(final URL url) {
        return pool.submit(new Callable<String>() {
            @Override
            public String call() throws Exception {
                try (InputStream input = url.openStream()) …