无法在 PC 上接收来自 Android phone 的 UDP 数据包

Question

我正在尝试在 PC 运行 Java UDP 服务器和 Android phone 运行 UDP 客户端之间建立一个简单的连接。 Android表示包裹已发送，但电脑没有收到任何东西。

两台设备在同一网络下，PC 通过以太网连接，IP 192.168.56.1，Android 通过 Wi-fi 连接。两者的端口都是2050，缓冲区大小都是1024。我正在尝试从 Android phone 发送一个 4 位数的 PIN，加上字符 #，再加上一个 4 位数的接受代码（在本例中为 0001），因此消息类似于 2348#0001 . PC 应接收包并解码此消息。

服务器（PC）代码（它永远保留在接收中）：

private boolean connect() throws Exception{
    System.out.println("Waiting for PIN code...");
    String msg;
    byte[] buffer = new byte[BUFFER_SIZE];
    DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
    socket.receive(packet);
    System.out.println("Received packet");
    msg = new String(packet.getData()).trim();
    String[] msgDecoded = msg.split("#");
    clientIP = packet.getAddress();

    if(msgDecoded[0].equals(password) && msgDecoded[1].equals(CONNECTION_ACCEPT_CODE)) return true;
    else return false;
}

客户（Androidphone）代码：

public void establishConnection(View view) throws Exception{

    /* Variable assignments and initializations */
    clientSocket = new DatagramSocket();
    serverIP = ((EditText)findViewById(R.id.ipInput)).getText().toString();
    Log.d("Info", "IP ADDRESS: " + serverIP);
    InetAddress IPAddress = InetAddress.getByName(serverIP);
    final String password = ((EditText) findViewById(R.id.passwordInput)).getText().toString();
    String message = password + "#" + CONNECTION_ACCEPT_CODE;
    data = message.getBytes();
    final DatagramPacket sendPacket = new DatagramPacket(data, data.length, IPAddress, DEFAULT_PORT);

    /* Send the data to the server */
    /* Needs to be done in another thread, otherwise NetworkOnMainThreadException is thrown */
    Thread sendThread = new Thread(new Runnable() {
        @Override
        public void run(){
            try{ clientSocket.send(sendPacket); Log.d("TEST", "Sent" + sendPacket.getData().toString());}
            catch (Exception e){ Log.d("TEST", "EXCEPTION SENDING"); }
        }
    });
    sendThread.start();


    /* Now wait for server ACK */
    receiveData = new byte[BUFFER_SIZE];
    final DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);

    /* Receive data from the server */
    /* Needs to be done in another thread, otherwise NetworkOnMainThreadException is thrown */
    Thread receiveThread = new Thread(new Runnable() {
        @Override
        public void run(){
            try{
                clientSocket.receive(receivePacket);
                Log.d("RECEIVED", receivePacket.getData().toString());
                String ack = new String(receivePacket.getData(), StandardCharsets.UTF_8);
                /* If receive ACK go to next activity */
                if(ack.equals(ACK_ACCEPTED)){
                    Intent intent = new Intent(getApplicationContext(), KeylogActivity.class);
                    intent.putExtra(EXTRA_IPADDR, serverIP);
                    intent.putExtra(EXTRA_PASSWD, password);
                    startActivity(intent);
                }

                /* If we don't, log error */
                // TODO: do actual job here
                else{
                    Log.d("[Error]", "Server rejected the connection: " + ack);
                }

            }
            catch (Exception e) { Log.d("ERROR", "Exception receiving: " + e); }
        }
    });
    receiveThread.start();
}

SendThread 似乎工作正常，因为它记录 "Sent"，但它在 PC 上没有效果。由于 PC 服务器不接收消息，它也不发送任何消息，因此 Android phone 不接收任何消息。

Answer 1

好的，问题是我试图连接到 VirtualBox Host-Only 网络。我运行在 Powershell 上使用命令 ipconfig 并看到了我的真实 IP。更改应用程序中的 IP 以匹配以太网接口 one 解决了我的问题。

无法在 PC 上接收来自 Android phone 的 UDP 数据包

Unable to receive UDP packet on PC from Android phone

networking

android

udp