java - 如何使这个非阻塞服务器成为多线程的？

Question

我正在尝试允许多个连接到一个小型 Java 服务器类型的应用程序。它按原样工作正常，但如果一个连接打开然后挂起，则所有后续连接都将挂起。我不确定如何处理每个连接，最多大约 20 个并发连接在它们自己的线程中，同时跟踪哪个线程属于哪个客户端等。我目前的代码是:

private void init() {
    try {
        // Create the server socket channel
        ServerSocketChannel server = ServerSocketChannel.open();
        // nonblocking I/O
        server.configureBlocking(false);
        // host-port 
        server.socket().bind(new InetSocketAddress(host, port));
        System.out.println("Server connected on " + host + ":" + port);
        // Create the selector
        Selector selector = Selector.open();
        // Recording server to selector (type OP_ACCEPT)
        server.register(selector, SelectionKey.OP_ACCEPT);
        // Infinite server loop
        for (;;) {
            // Waiting for events
            selector.select();
            // Get keys
            Set keys = selector.selectedKeys();
            Iterator i = keys.iterator();
            // For each keys...
            while (i.hasNext()) {
                SelectionKey key = (SelectionKey) i.next();
                // Remove the current key
                i.remove();
                // if isAccetable = true
                // then a client required a connection
                if (key.isAcceptable()) {
                    // get client socket channel
                    SocketChannel client = server.accept();
                    // Non Blocking I/O
                    client.configureBlocking(false);
                    // recording to the selector (reading)
                    client.register(selector, SelectionKey.OP_READ);
                    continue;
                }
                // then the server is ready to read
                if (key.isReadable()) {
                    SocketChannel client = (SocketChannel) key.channel();
                    // Read byte coming from the client
                    int BUFFER_SIZE = 32;
                    ByteBuffer buffer = ByteBuffer.allocate(BUFFER_SIZE);
                    try {
                        client.read(buffer);
                    } catch (Exception e) {
                        // client is no longer active
                        e.printStackTrace();
                        continue;
                    }
                    buffer.flip();
                    Charset charset = Charset.forName("ISO-8859-1");
                    CharsetDecoder decoder = charset.newDecoder();
                    CharBuffer charBuffer = decoder.decode(buffer);
                    Handler dataHandler = new Handler();
                    client.write(ByteBuffer.wrap(dataHandler.processInput(charBuffer.toString()).getBytes()));
                    client.socket().close();
                    continue;
                }
            }
        }
    } catch (IOException ex) {
        Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, ex);
    }
}

Answer 1

每当我需要编写套接字服务器时，我都会避免使用低级 JVM 类，因为需要处理所有细节。

相反，我使用 Apache Mina .这是一个用于编写高性能非阻塞多线程套接字服务器的 Java 库。

使用 Mina 的另一个好处是它强制执行 clean architecture (IoFilters、协议(protocol)解码器)使您的代码更加模块化并更易于维护。