C# (ASP.NET) 通过 Sockets 与 android 通信

Question

我已经研究这个问题有一段时间了。我有基本概念，现在尝试实现 ASP.NET 和 android 之间的套接字通信。 我正在使用基本的窗口System.Net.Sockets 来解决这个问题。当我尝试逐行调试我的应用程序时，我得到了一个连接，这告诉我我的服务器正在工作，但问题是 C# 行卡在sender.Receive(bytes)。

这是我用于 TCPServer 的 android 端服务器代码

public class TCPServer extends Thread {
    public static final int SERVER_PORT = 11000;
    private boolean running = false;
    private PrintWriter mOut;
    private OnMessageReceived messageListener;


    public TCPServer(OnMessageReceived messageListener)
    {
        this.messageListener = messageListener;
    }

    public void sendMessage(String message)
    {
        if(mOut != null && !mOut.checkError())
        {
            mOut.println(message);
            mOut.flush();
        }
    }

    @Override
    public void run()
    {
        super.run();
        running=true;
        try {
            ServerSocket serverSocket = new ServerSocket(SERVER_PORT);
            Socket client = serverSocket.accept();
            try {
                //sends the message to the client
                mOut = new PrintWriter(new BufferedWriter(new OutputStreamWriter(client.getOutputStream())), true);

                //read the message received from client
                BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));

                //in this while we wait to receive messages from client (it's an infinite loop)
                //this while it's like a listener for messages
                while (running) {
                    String message = in.readLine();

                    if (message != null && messageListener != null) {

                        messageListener.messageReceived(message);
                        sendMessage("OK Message is received here");
                        //the line above and below is also not helping me with my problem
                        mOut.println("OK: FROM ACOM");
                    }
                }
            }
            catch (Exception e)
            {
                e.getMessage();
            }
            finally {
                client.close();
            }
        }
        catch (Exception e)
        {
            e.getMessage();
        }
    }

    public interface OnMessageReceived {
        public void messageReceived(String message);
    }
}

这就是我从我的主要活动中调用它的方式，目前使用一个简单的按钮来启动服务器以像这样进行监听

btnStartServer.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(context,"Starting the server",Toast.LENGTH_LONG).show();
               TCPServer tcpServer = new TCPServer(new TCPServer.OnMessageReceived() {
                   @Override
                   public void messageReceived(String message) {
                      txtMessageReceived.setText(message);
                   }
               });
                tcpServer.start();

            }
        });

现在至于 C# 或 ASP.NET，我刚刚在 webforms 页面上添加了一个简单的按钮来进行测试，这就是它的代码

        IPAddress ipAddress;
        IPEndPoint remoteEP;
        Socket sender;
        byte[] bytes;
  private void setUpSockets()
        {
            bytes = new byte[1024];
            try
            {
                ipAddress = IPAddress.Parse("192.168.0.102");
                remoteEP = new IPEndPoint(ipAddress, 11000);
                sender = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                try
                {
                    sender.Connect(remoteEP);
                    byte[] msg = Encoding.ASCII.GetBytes("This is some Test <EOF>");
                    int byteSent = sender.Send(msg);
                    int byteRec = sender.Receive(bytes);
                    string messageRec = Encoding.ASCII.GetString(bytes, 0, byteRec);

                    sender.Shutdown(SocketShutdown.Both);
                    sender.Close();
                }
                catch (Exception e)
                {
                    string exception = e.Message;
                }
            }
            catch (Exception m)
            {
                string exception = m.Message;
            }
        }
  protected void Button1_Click(object sender, EventArgs e)
        {
            setUpSockets();
        }

现在我只是在将它添加到有意义的东西之前对其进行测试，但我被困在int byteRec = sender.Receive(bytes); 上，我不确定我应该怎么做，因为正如你所看到的，我也在尝试从 android 客户端发送一些响应。就像它卡在这条线上等待它永远不会收到的响应，而且 android 端的文本框也没有更新收到的任何内容。

Answer 1

我一直在尝试找出正确的方法来做到这一点，但问题是我需要确定两种语言的编码，并确保在接收数据之前接收到任一端的字节。 This 问题很有帮助，我能够使代码工作

进行了以下更改并且有效

C#端

 bytes = new byte[1024];
            try
            {
                ipAddress = IPAddress.Parse("192.168.0.128");
                remoteEP = new IPEndPoint(ipAddress, 11000);
                sender = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                try
                {
                    string toSend = TextBox1.Text;

                    sender.Connect(remoteEP);
                    //sending
                    int toSendLen = System.Text.Encoding.ASCII.GetByteCount(toSend);
                    byte[] toSendBytes = System.Text.Encoding.ASCII.GetBytes(toSend);
                    byte[] toSendLenBytes = System.BitConverter.GetBytes(toSendLen);
                    //Console.WriteLine("Soccket connected to{0}", sender.RemoteEndPoint.ToString());
                    sender.Send(toSendLenBytes);
                    sender.Send(toSendBytes);

                    //Receiving

                    byte[] rcvLenBytes = new byte[4];
                    sender.Receive(rcvLenBytes);
                    int rcvLen = System.BitConverter.ToInt32(rcvLenBytes, 0);
                    byte[] rcvBytes = new byte[rcvLen];
                    sender.Receive(rcvBytes);
                    String rcv = System.Text.Encoding.ASCII.GetString(rcvBytes);
                    TextBox1.Text = rcv;


                    //----------------OLD----------------------------
                    //  byte[] msg = Encoding.ASCII.GetBytes("This is some Test.");
                    //  TextBox1.Text = msg.ToString();
                    //  int byteSent = sender.Send(msg);
                    //  TextBox1.Text += "Bytes Sent = " + byteSent;

                    ////  System.Threading.Tasks.Task.Delay(1000).Wait();
                    //  int byteRec = sender.Receive(bytes);
                    //  string messageRec = Encoding.ASCII.GetString(bytes, 0, byteRec);
                    //  Console.WriteLine("Response from remote Device {0}", messageRec);
                    //  TextBox1.Text += "\nmessageRec = " + messageRec;
                    sender.Shutdown(SocketShutdown.Both);
                    sender.Close();
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                }
            }
            catch (Exception m)
            {
                Console.WriteLine(m.Message);
            }

安卓端

        ServerSocket serverSocket = new ServerSocket(11000, 10);
        Socket socket = serverSocket.accept();
        InputStream is = socket.getInputStream();
        OutputStream os = socket.getOutputStream();

        // Receiving
        byte[] lenBytes = new byte[4];
        is.read(lenBytes, 0, 4);
        int len = (((lenBytes[3] & 0xff) << 24) | ((lenBytes[2] & 0xff) << 16) |
                  ((lenBytes[1] & 0xff) << 8) | (lenBytes[0] & 0xff));
        byte[] receivedBytes = new byte[len];
        is.read(receivedBytes, 0, len);
        String received = new String(receivedBytes, 0, len); 
        // Sending
        String toSend = "Echo: " + received;
        byte[] toSendBytes = toSend.getBytes();
        int toSendLen = toSendBytes.length;
        byte[] toSendLenBytes = new byte[4];
        toSendLenBytes[0] = (byte)(toSendLen & 0xff);
        toSendLenBytes[1] = (byte)((toSendLen >> 8) & 0xff);
        toSendLenBytes[2] = (byte)((toSendLen >> 16) & 0xff);
        toSendLenBytes[3] = (byte)((toSendLen >> 24) & 0xff);
        os.write(toSendLenBytes);
        os.write(toSendBytes);

        socket.close();
        serverSocket.close();

上面提到的android代码在方法run的TCPServer类中更新了。