Android telnet client issue

Question

I'm new at developing at android OS. I try developing my telnet client for android OS. Now, I only try to connect telnet server, and receive login message.

But when I start socket to connect telnet server Ihave received strange symbols ??????!???? instead the logon message from telnet server.

public class MainActivity extends Activity {
    protected static final int TCP_SERVER_PORT = 23;
    protected String inMsg, str;
    static Editable sentence;
    static String modifedSentence;
    BufferedReader inFromUser;
    Socket clientSocket = null;
    DataOutputStream outToServer=null;
    BufferedReader inFromServer=null;        

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button startButton = (Button)findViewById(R.id.startButton);
        final TextView textView = (TextView)findViewById(R.id.textView);

        startButton.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View arg0) {
                new Thread(new Runnable() {                   

                    @Override
                    public void run() {             

       //Create socket
        try {
        clientSocket = new Socket("192.168.1.1",23);
       //Create out stream for ClientSocket
            outToServer = new DataOutputStream(clientSocket.getOutputStream());
       //Create ib stream for ClientSocket          
        inFromServer = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
       //Receive login message from telnet server
            modifedSentence = inFromServer.readLine();
        } catch (UnknownHostException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        }
                 //Update UI activity with login message
         MainActivity.this.runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                          textView.setText(modifedSentence);
                    }
                });   
        }
             }).start();
    }   
        });         
    }

   protected void onDestroy()
    {
        try {
            clientSocket.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

Can you print the values of bytes which generate the strange symbols and tell us what they are? — Robᵩ, Mar 01 '13 at 18:39
Consider if [this question](http://stackoverflow.com/questions/10413963/telnet-iac-command-answering/10418479#10418479) sheds light on your problem. — Robᵩ, Mar 01 '13 at 18:41
thanks, you are right. telnet is not a simple tcp connection — Dmitry Faddeev, Mar 29 '13 at 12:03
In that case, consider using a telnet library like `org.apache.commons.net.telnet.*`. — Robᵩ, Mar 29 '13 at 13:13

score 0 · Answer 1 · answered Mar 01 '13 at 11:07

0

These "strange" symbols ??????!???? mean, that you use wrong encoding. When you create InputStreamReader you should explicitly point which encoding this stream should use. I don't known which encoding is used inside your telnet service, but you can try various of them, e.g. windows-1252:

new InputStreamReader(clientSocket.getInputStream(), Charset.forName("windows-1252"))

answered Mar 01 '13 at 11:07

Andremoniy

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Andremoniy Thanks a lot for your replies. I try "windows-1252" "UTF-8" "ASCII" "US-ASCII" no luck – Dmitry Faddeev Mar 01 '13 at 12:00

score 0 · Answer 2 · answered Mar 29 '13 at 11:34

0

Telnet app require telnet protocol for connections to the telnet server. It's not a simple tcp connection. I use apache commonse library which provide class for telnet accessing. Thanks

answered Mar 29 '13 at 11:34

Dmitry Faddeev

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2

Android telnet client issue

2 Answers2