Question

我一直在开发一个与Java联网的程序，该程序使用this tutorial之后的NIO选择器，并且由于某种原因，当我尝试与朋友（在另一个网络中相距较远）测试该程序时，它不起作用即使当我尝试仅在计算机上自己进行测试时，它也可以正常工作。
以下是该问题的相关代码：

EchoServer类（一个线程）：

private Selector selector;
private ServerSocketChannel serverSocket;
private boolean stop = false;
private List<String> pendingStrings;

public EchoServer() throws IOException {
    // Get selector
    this.selector = Selector.open();
    System.out.println("Selector open: " + selector.isOpen());
    // Get server socket channel and register with selector
    this.serverSocket = ServerSocketChannel.open();
    InetSocketAddress hostAddress = new InetSocketAddress("", NetworkingSettings.PORT);
    serverSocket.bind(hostAddress);
    serverSocket.configur eBlocking(false);
    int ops = serverSocket.validOps();
    SelectionKey selectKy = serverSocket.register(selector, ops, null);
    this.pendingStrings = new ArrayList<>();
}

@Override
public void run() {
    while (!stop) {
        try {
            update();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

private void update() throws IOException {
    System.out.println("Waiting for select...");
    int noOfKeys = selector.select();

    System.out.println("Number of selected keys: " + noOfKeys);

    Set selectedKeys = selector.selectedKeys();
    Iterator iter = selectedKeys.iterator();

    while (iter.hasNext()) {

        SelectionKey ky = (SelectionKey) iter.next();
        if (ky.isAcceptable()) {
            acceptClient();
        }
        else if (ky.isReadable()) {
            readDataFromClient(ky);
        }
        iter.remove();
    }
}

EchoClient类：

private SocketChannel client;
private InetSocketAddress hostAddress;
private boolean connected;

public EchoClient(String ip) {
    this.hostAddress = new InetSocketAddress(ip, NetworkingSettings.PORT);
    connected = false;
}

public void connect() throws IOException {
    if (!connected) {
        client = SocketChannel.open(hostAddress);
        connected = true;
    }
}

public void sendMessage(String message) throws IOException {
    try {
        byte[] messageBytes = message.getBytes();
        ByteBuffer buffer = ByteBuffer.wrap(messageBytes);
        client.write(buffer);
        buffer.clear();
    } catch (IOException e) {
        cleanUp();
    }
}

现在，问题似乎出在服务器上，因为当我的朋友运行服务器时（我是客户端），我什至无法连接到服务器。我怀疑问题的根源是 EchoServer 中的那些行：

InetSocketAddress hostAddress = new InetSocketAddress("", NetworkingSettings.PORT);
serverSocket.bind(hostAddress);

但是我似乎无法弄清楚到底是什么。

重要说明： NetworkingSettings.PORT是80，我知道它是用于http的端口，也许是问题所在，但我真的想避免使用端口转发和防火墙设置

Answer 1

问题在于<View style={{flex:1, flexDirection:'column'}}> <Image .... /> <Text>text here</Text> </View>绑定到的InetSocketAddress。要允许本地主机和远程网络接口上的连接，您需要绑定到通配符地址。这可以通过只使用端口号的ServerSocketChannel constructor来完成：

InetSocketAddress

不使用localhost

1 个答案: