Class JavaAsyncHTTPServer

javaws/src/JavaAsyncHTTPServer.java:13–72

import java.util.concurrent.ExecutionException;

public class JavaAsyncHTTPServer {
    public static void main(String[] args) throws Exception {
        new JavaAsyncHTTPServer().start();
        Thread.currentThread().join(); // Wait forever
    }

    private void start() throws IOException {
        // we shouldn't use try with resource here as it will kill the stream
        var server = AsynchronousServerSocketChannel.open();
        server.bind(new InetSocketAddress("127.0.0.1", 8080), 100); // bind listener
        server.setOption(StandardSocketOptions.SO_REUSEADDR, true);
        System.out.println("Server is listening on port 8080");

        final int[] count = {0}; // count used to introduce delays

        // listen to all incoming requests
        server.accept(null, new CompletionHandler<>() {
            @Override
            public void completed(final AsynchronousSocketChannel result, final Object attachment) {
                if (server.isOpen()) {
                    server.accept(null, this);
                }
                count[0]++;
                handleAcceptConnection(result, count[0]);
            }

            @Override
            public void failed(final Throwable exc, final Object attachment) {
                if (server.isOpen()) {
                    server.accept(null, this);
                    System.out.println("Connection handler error: " + exc);
                }
            }
        });
    }

    private void handleAcceptConnection(final AsynchronousSocketChannel ch, final int count) {
        var file = new File("hello.html");
        try (var fileIn = new FileInputStream(file)) {
            // add 2 second delay to every 10th request
            if (count % 10 == 0) {
                System.out.println("Adding delay. Count: " + count);
                Thread.sleep(2000);
            }
            if (ch != null && ch.isOpen()) {
                // Read the first 1024 bytes of data from the stream
                final ByteBuffer buffer = ByteBuffer.allocate(1024);
                // read the request fully to avoid connection reset errors
                ch.read(buffer).get();

                // read the HTML file
                var fileLength = (int) file.length();
                var fileData = new byte[fileLength];
                fileIn.read(fileData);

                // send HTTP Headers
                var message = ("HTTP/1.1 200 OK\n" +
                        "Connection: keep-alive\n" +