Question

我尝试将十六进制字节数组发送到服务器，我也会收到字节数组响应这是一个来源

    public void sendActivationApduToServer(final String command) {
    class ClientAsycTask extends AsyncTask<String, Void, String> {
        ProgressDialog progress;
        DataOutputStream dataOutputStream = null;

        @Override
        protected void onPreExecute() {
            progress = new ProgressDialog(CardReader.this);
            progress.setMessage("Connection Server Please wait");
            progress.setIndeterminate(true);
            progress.show();
        }

        @Override
        protected String doInBackground(String... params) {
            String result = null;
            Socket socket = new Socket();
            DataInputStream dataInputStream;
            try {
                socket.connect(new InetSocketAddress(SERVER_IP, SERVER_PORT));
                dataOutputStream = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));
                dataInputStream = new DataInputStream(new BufferedInputStream(socket.getInputStream()));

                byte[] messages = hexStringToByteArray(command);
                dataOutputStream.writeInt(messages.length);
                dataOutputStream.write(messages);

                int length = dataInputStream.readInt();
                String response = "";
                if (length > 0) {
                    byte[] message = new byte[length];
                    dataInputStream.readFully(message, 0, message.length); // read the message
                    response= keyrandom.bytesToHexString(message);

                }
                Log.e("server response",response+"server response");

                socket.close();

            } catch (Exception e) {
                e.printStackTrace();
                Log.e("server exception",e.getMessage());
            }
            return result;
        }

        @Override
        protected void onPostExecute(String s) {
            if (progress.isShowing()) {
                progress.dismiss();
            }
            Toast.makeText(CardReader.this, "Connected " + s, Toast.LENGTH_SHORT).show();
        }
    }
    ClientAsycTask clientAsycTask = new ClientAsycTask();
    clientAsycTask.execute();
}




 public static String bytesToHexString(byte[] src) {
    StringBuilder stringBuilder = new StringBuilder();
    if (src == null || src.length <= 0) {
        return null;
    }
    for (int i = 0; i < src.length; i++) {
        int v = src[i] & 0xFF;
        String hv = Integer.toHexString(v);
        if (hv.length() < 2) {
            stringBuilder.append(0);
        }
        stringBuilder.append(hv);
    }
    return stringBuilder.toString();
}






   public static byte[] hexStringToByteArray(String s) {
    s = s.replace(" ", "");
    s = s.replace("\n", "");
    int len = s.length();
    byte[] data = new byte[len / 2];
    for (int i = 0; i < len; i += 2) {
        data[i / 2] = (byte) ((Character.digit(s.charAt(i), 16) << 4)
                + Character.digit(s.charAt(i + 1), 16));
    }
    return data;
}

当我运行我的应用程序时，我有异常

java.net.SocketException: recvfrom failed: ETIMEDOUT (Connection timed out)

int this line

int length = dataInputStream.readInt();

任何人都可以告诉我应该是什么问题？我尝试在全局IP地址和全局端口发送字节数组，而不是本地。我测试了连接有什么建议吗？

SocketException：recvfrom失败：Java中的ETIMEDOUT

0 个答案: