Develop Reference

android bufferReader.readLine() returns rubbish data from C# TCP client occasionally?

i have build a chat application that uses UDP and TCP sockets, first let me walk you through the mechanism of the app:
from the android device i send a UDP packet to a group address which has multiple windows devices listening to it, when the windows device receives the packet, it checks whether it has the same phone number or not so i use the phone number as a unique key to identify the device then if it has the same phone number that I've send the packet with, it will respond with a key says: "ImReadyNow" sent through a TCP socket and that will make the android device accept the connection and act as a server for that windows device, i had similar problems when i first start making that app, the respond key from the windows device was returned with some rubbish data before and after it and i solved that problem by attaching a key to that massage and i split it after releasing so that old problem that i was facing was when a windows device sends "Hello" the android device receives
"????Hello" i solved this one by attaching a key to the first of the massage so
i'll receives "????$#!Hello" then i'll split the received string into two parts and displays the massage only, and that works fine for me till, i notice that sometimes the android device receives rubbish data only and that occurs randomly like if windows device sends "hello" then "hi" then "hello"
i may receives the first two massages right but the third one will received as "?????"
and as i told you it occurs randomly so does any one know why is this happening?
after debugging br.readLine() method does sometimes return "????" and this occurs as i said randomly.
here is the code that i'm using:
private class ChatClientThread extends Thread {
#Override
public void run() {
/*Socket socket = null;
DataOutputStream dataOutputStream = null;
DataInputStream dataInputStream=null;*/
// clientSocket=null;
try {
String data=EmpPhoneNumber;
DatagramChannel channel = DatagramChannel.open();
DatagramSocket socket = channel.socket();
socket.setReuseAddress(true);
socket.bind(new InetSocketAddress(52276));
socket.setBroadcast(true);
InetAddress group = InetAddress.getByName(
"224.0.1.2");
System.out.println("HELLO");
System.out.println(data);
DatagramPacket packet = new DatagramPacket(data.getBytes(), data.length(),
group, 52276);
serverSocket=new ServerSocket();
serverSocket.setReuseAddress(true);
serverSocket.bind(new InetSocketAddress(4125));
int i=0;
while(i<=30){
Thread.sleep(200);
socket.send(packet);
i++;
}
while(true){
clientSocket = serverSocket.accept();
BufferedReader br= new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
strAcceptConnection= br.readLine();
System.out.println(strAcceptConnection);
if(!strAcceptConnection.contains("$#!")){
updateTextView("<font color=\"#0000A0\"> <b>"+empNameChat+": </b></font>"+"Error in recieving msg");
}else{
String parts[]= strAcceptConnection.split("[$#!]+");
if(!parts[1].equals("ImReadyNoW")){
updateTextView("<font color=\"#0000A0\"> <b>"+empNameChat+": </b></font>"+parts[2]);
}}}
} catch (UnknownHostException e) {
e.printStackTrace();
final String eString = e.toString();
EmpDetails.this.runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(EmpDetails.this, eString, Toast.LENGTH_LONG).show();
}
});
} catch (IOException e) {
e.printStackTrace();
final String eString = e.toString();
EmpDetails.this.runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(EmpDetails.this, eString, Toast.LENGTH_LONG).show();
}
});
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}catch (NullPointerException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}catch(Exception e){
e.printStackTrace();
} finally {
EmpDetails.this.runOnUiThread(new Runnable() {
#Override
public void run() {
}
});
}
}
}
public void sendMessage(View view) {
final String msg= et.getText().toString();
et.setText("");
new Thread(new Runnable() {
public void run() {
Socket sock= null;
try {
sock= new Socket(clientSocket.getInetAddress().getHostAddress(), 4125);
Log.v("str", "send sock: "+sock.getInetAddress().getHostAddress()+sock.isConnected()+Integer.toString(sock.getPort()));
} catch (UnknownHostException e) {
Log.v("ERRORTAG", ""+e.getMessage());
e.printStackTrace();
} catch (IOException e) {
Log.v("ERRORTAG", ""+e.getMessage());
e.printStackTrace();
}catch (Exception e) {
e.printStackTrace();
}
try {
DataOutputStream out= new DataOutputStream(sock.getOutputStream());
if(!msg.equals("")){
out.writeUTF("XX$#!"+MainActivity.empIdFromD+"$#!"+msg);
out.flush();
updateTextView("<font color=\"#800000\"> <b>"+"You"+": </b></font>" + msg);}
}
catch (IOException e) {
Log.v("ERRORTAG", ""+e.getMessage());
e.printStackTrace();
}
}
}).start();
}
public void updateTextView(String message) {
final String msg= message;
uiHandle.post(new Runnable() {
public void run() {
textView.setMovementMethod(new ScrollingMovementMethod());
Log.v("TAG", "updating textview");
//textView.append(msg+"\n");
textView.append(Html.fromHtml(msg));
textView.append("\n");
Log.v("TAG", "updated textview");
ScrollView sc= (ScrollView)findViewById(R.id.scrollView1);
sc.fullScroll(View.FOCUS_DOWN);
}
});
}
how does the received string look like:
LogCat:
PS. on the other side the windows device receives all of the massages correctly.

C# server and Android Client

I'm working on two programs, one software Microsoft visual studio 2010 when I run a server and a second program : Eclipse ADT (ANDROID device development environment) in which I supposedly client. The goal is to establish a connection between SERVER in C# and Android CLIENT. It should not be a problem, I tried on TCP and UDP tried on, it falls on both object creation context (in TCP that falls on the object socket and UDP SOCKET falls DATAGRAM object creation), it seems to me the problem is: activitythread.performlaunchactivity (activitythread $ activityclientreco rd intent) line 2247
As I understand the problem is not in my code snippet but the SOCKET supplementation with software built into Eclipse, I tried to re-install, add the latest plugin. To your next question, I did permissions for Android device and internet. This I have no idea how to approach this problem which I am going for a month or more ..
In addition I'll add my code in android client :
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStreamWriter;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;
import android.util.Log;
public class MainActivity extends Activity {
private TextView txt;
private Button b;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b = (Button)findViewById(R.id.button1);
txt = (TextView)findViewById(R.id.textView1);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
connectSocket("Hello");
}
});
}
private void connectSocket(String a){
try {
InetAddress serverAddr = InetAddress.getByName("10.0.0.8");
Log.d("TCP", "C: Connecting...");
**Socket socket = new Socket(serverAddr, 4444);**
String message = "1";
PrintWriter out = null;
BufferedReader in = null;
try {
Log.d("TCP", "C: Sending: '" + message + "'");
out = new PrintWriter( new BufferedWriter( new OutputStreamWriter(socket.getOutputStream())),true);
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
out.println(message);
while ((in.readLine()) != null) {
txt.append(in.readLine());
}
Log.d("TCP", "C: Sent.");
Log.d("TCP", "C: Done.");
} catch(Exception e) {
Log.e("TCP", "S: Error", e);
} finally {
socket.close();
}
} catch (UnknownHostException e) {
// TODO Auto-generated catch block
Log.e("TCP", "C: UnknownHostException", e);
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
Log.e("TCP", "C: IOException", e);
e.printStackTrace();
}
}
}
and my server in C# :
using System;
using System.Text;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Sockets;
public class TestTCP
{
public static void Main()
{
try
{
IPAddress ipAd = IPAddress.Parse("127.0.0.1");
// use local m/c IP address, and
// use the same in the client
/* Initializes the Listener */
TcpListener myList = new TcpListener(ipAd, 11000);
/* Start Listeneting at the specified port */
myList.Start();
Console.WriteLine("The server is running at port 11000...");
Console.WriteLine("The local End point is :" +
myList.LocalEndpoint);
Console.WriteLine("Waiting for a connection.....");
m:
Socket s = myList.AcceptSocket();
Console.WriteLine("Connection accepted from " + s.RemoteEndPoint);
byte[] b = new byte[100];
int k = s.Receive(b);
char cc = ' ';
string test = null;
Console.WriteLine("Recieved...");
for (int i = 0; i < k - 1; i++)
{
Console.Write(Convert.ToChar(b[i]));
cc = Convert.ToChar(b[i]);
test += cc.ToString();
}
switch (test)
{
case "1":
break;
}
ASCIIEncoding asen = new ASCIIEncoding();
s.Send(asen.GetBytes("The string was recieved by the server."));
Console.WriteLine("\nSent Acknowledgement");
/* clean up */
goto m;
s.Close();
myList.Stop();
Console.ReadLine();
}
catch (Exception e)
{
Console.WriteLine("Error..... " + e.StackTrace);
}
}
}
Thanks.

First of all you may not run the connecSocket method in your UI thread. You have to do something like this:
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Thread stackOverflow = new Thread(new Runnable() {
#Override
public void run() {
connectSocket("Hello");
}});
stackOverflow.start();
}
});
Otherwise you get this exception:
android.os.NetworkOnMainThreadException
Secondly you must connect to the same port and interface where your server is listening:
IPAddress ipAd = IPAddress.Parse("127.0.0.1");
Should be the same address as the one you are using in your Android application:
IPAddress ipAd = IPAddress.Parse("10.0.0.8");
And your Android application must connect to the same port where server is listening:
Socket socket = new Socket(serverAddr, 11000);
Finally do not forget the Android permissions:
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
And be careful with firewalls and things like that, they could also drop your connections.

C# Client and Android Listener

i am new to this website but have been reading alot since long.
I am little confused with this IP stuff, i am reasonable programmer but very poor at IP thing.
I want to implement C# client with Android Server[Android device moves around the world so first thing is to get its IP address].
I have written[copied] following android code from stackOverflow question and trying to use it.
public static String getLocalIpAddress() {
try {
for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
NetworkInterface intf = en.nextElement();
for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {
InetAddress inetAddress = enumIpAddr.nextElement();
if (!inetAddress.isLoopbackAddress()) {
String ip = Formatter.formatIpAddress(inetAddress.hashCode());
Log.i("IP", "***** IP="+ ip);
return ip;
}
}
}
} catch (SocketException ex) {
Log.e("EXCPTN", ex.toString());
}
return null;
}
Question 1: It gives me some Ip lets say 142.171.13.206 , but when i check my Ip by googling 'what is my ip' from my andoird decide, i totally get new IP [120.100.78.14]. What wrong i am doing? I am running on Wifi, no edge no 3g or something.
Question 2: If i have a C# client, which android IP should i try to connect ? Becuase i am unable to connect to android server.
My C# Client code is something like this
try
{
const int Port = 4321;
TcpClient ourMagicClient = new TcpClient();
//Connect to the server - change this IP address to match your server's IP!
ourMagicClient.Connect("192.177.111.200", Port);
//Use a NetworkStream object to send and/or receive some data
NetworkStream ourStream = ourMagicClient.GetStream();
//Let's set up some data!
byte[] data = Encoding.ASCII.GetBytes("Plz recieve this msg!");
//Everyone ready? Send that bad-boy!
ourStream.Write(data, 0, data.Length); //Start at the 0'th position in our string and send until the end of the string, but we can stop there...
}
catch (Exception ex)
{
textBox1.Text = ex.ToString();
}
And finally here is the code for my android listener running 4.4 Kitkat
private class SocketServerThread extends Thread {
static final int SocketServerPORT = 4321;
int count = 0;
#Override
public void run() {
try {
serverSocket = new ServerSocket(SocketServerPORT);
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
info.setText("I'm waiting here: "
+ serverSocket.getLocalPort());
;
}
});
while (true) {
Socket socket = serverSocket.accept();
count++;
message += "#" + count + " from " + socket.getInetAddress()
+ ":" + socket.getPort() + "\n";
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
msg.setText(message);
}
});
SocketServerReplyThread socketServerReplyThread = new SocketServerReplyThread(
socket, count);
socketServerReplyThread.run();
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
private class SocketServerReplyThread extends Thread {
private Socket hostThreadSocket;
int cnt;
SocketServerReplyThread(Socket socket, int c) {
hostThreadSocket = socket;
cnt = c;
}
#Override
public void run() {
OutputStream outputStream;
String msgReply = "Hello from Android, you are #" + cnt;
try {
outputStream = hostThreadSocket.getOutputStream();
PrintStream printStream = new PrintStream(outputStream);
printStream.print(msgReply);
printStream.close();
message += "replayed: " + msgReply + "\n";
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
msg.setText(message);
}
});
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
message += "Something wrong! " + e.toString() + "\n";
}
MainActivity.this.runOnUiThread(new Runnable() {
#Override
public void run() {
msg.setText(message);
}
});
}
}
I have googles alot, searched this website too, but i am unable to connect C# client with Andoird server. Plz help me with the code what n where to fix. Or if you have totally different working code plz share that with me.
Note: Thx to all those from which i have copied above code [unfortunately i dont have referece to thier websites]. Thx!

C# Multicast UDP connection, BeginReceiveFrom async call stops to be called

this is my first post, sorry in advance if I do something I shouldn't. I always search here for answer but this time I saw nothing about my problem. I have a project in C# where I keep alive a connection UDP listening a multicast IP from a data streaming.
The IP I'm listening is a multicast streamer that sends tracking data from many tracking systems, so we can assume the sender is not the problem. It sends like 1024 bytes packets, 60 fps.
This is a small example extracted from the whole project, simplified and as far as I tested, behaves in the same way as in the big project. The problem is that if I connect in localhost this never break, but if I connect to remote IPs this stop working, more or less, in 4 minutes.
public class TrackingStateObject
{
public Socket workSocket = null;
public const int BUFFER_SIZE = 65507;
public byte[] buffer = new byte[BUFFER_SIZE];
}
class MainClass
{
static public string multicastServerIPAddress = "239.255.42.99";
static public string realTrackingServerIPAddress = "161.116.27.144";
static protected EndPoint trackingEndPoint;
static public int dataPort = 2345;
static protected Socket sockData = null;
static int foo = 0;
public static void Main (string[] args)
{
IPEndPoint ipep;
TrackingStateObject so;
IPAddress trackingIP = IPAddress.Parse(multicastServerIPAddress);
trackingEndPoint = new IPEndPoint(trackingIP, dataPort);
sockData = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
ipep = new IPEndPoint(IPAddress.Any, dataPort);
try {
sockData.Bind(ipep);
}
catch (Exception ex) {
System.Console.WriteLine("[UDPClient] Exception "+ex.Message);
return;
}
sockData.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, new MulticastOption(trackingIP));
try {
trackingIP = IPAddress.Parse(realTrackingServerIPAddress);
trackingEndPoint = new IPEndPoint(trackingIP, dataPort);
}
catch(Exception ex) {
System.Console.WriteLine("[UDPClient] Exception "+ex.Message);
return;
}
so = new TrackingStateObject();
so.workSocket = sockData;
sockData.BeginReceiveFrom(so.buffer, 0, TrackingStateObject.BUFFER_SIZE, 0, ref trackingEndPoint, new AsyncCallback(AsyncReceiveCallback), so);
System.Threading.Thread.Sleep (600000);
}
private static void AsyncReceiveCallback(IAsyncResult ar)
{
try {
TrackingStateObject so = (TrackingStateObject)ar.AsyncState;
Socket sock = so.workSocket;
int read = sock.EndReceiveFrom(ar, ref trackingEndPoint);
if (read > 0)
{
// Do things with the data
System.Console.WriteLine("Recieved shit, " + read + " bytes, " + foo++ + " times.");
}
sock.BeginReceiveFrom(so.buffer, 0, TrackingStateObject.BUFFER_SIZE, SocketFlags.None, ref trackingEndPoint, new AsyncCallback(AsyncReceiveCallback), so);
}
catch (Exception e) {
System.Console.WriteLine("[UDPClient] Exception AsynCallback "+e.Message);
}
}
}
I debugged for a while and as far I can see is that always sock.BeginReceiveFrom is called, stop in some point, AsyncReceiveCallback is never executed again. Perhaps I'm doing here something stupid, but in any case, I'm not able to see it. Thanks!

I was having exactly the same problem, which only seems to occur on WiFi interfaces, not hardwired interfaces. The solution I discovered was to always set the SocketOptionName.AddMembership option before calling BeginReceiveFrom().
In the receive callback, after calling EndReceiveFrom() then set the SocketOptionName.DropMembership option for the multicast address.
Then before calling BeginReceiveFrom() again, set the SocketOptionName.AddMembership option.
Not sure why this has to be done for WiFi interfaces, but it worked for me.

Sockets: Send strings from Java to C#?

I need to send string messages from Java program to C# program in real time.
There are many examples in the Internet but U can't find anything good for my purpose that is (probably) Java client (sockets code) and c# server (sockets code).
Thank you.

Ok i already did this in one of my projects so here it is:
disclaimer: some of the code (only a little bit actually) is based on nakov chat server.
also note that i decode and encode all the messages sent and recived in UTF-8.
Java Code:
Class: Server
import java.net.*;
import java.io.*;
import javax.swing.*;
public class Server
{
private static void createAndShowGUI() {
//Create and set up the window
}
public static final int LISTENING_PORT = 2002;
public static void main(String[] args)
{
// Open server socket for listening
ServerSocket serverSocket = null;
try
{
serverSocket = new ServerSocket(LISTENING_PORT);
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
//System.out.println("Server started on port " + LISTENING_PORT);
}
catch (IOException se)
{
System.err.println("Can not start listening on port " + LISTENING_PORT);
se.printStackTrace();
System.exit(-1);
}
// Start ServerDispatcher thread
ServerDispatcher serverDispatcher = new ServerDispatcher();
// Accept and handle client connections
while (true)
{
try
{
Socket socket = serverSocket.accept();
ClientInfo clientInfo = new ClientInfo();
clientInfo.mSocket = socket;
ClientListener clientListener =
new ClientListener(clientInfo, serverDispatcher);
ClientSender clientSender =
new ClientSender(clientInfo, serverDispatcher);
clientInfo.mClientListener = clientListener;
clientInfo.mClientSender = clientSender;
clientListener.start();
clientSender.start();
serverDispatcher.addClient(clientInfo);
}
catch (IOException ioe)
{
ioe.printStackTrace();
}
}
}
}
Class Message Dispatcher:
import java.io.UnsupportedEncodingException;
import java.net.*;
import java.util.*;
public class ServerDispatcher
{
private Vector mMessageQueue = new Vector();
private Vector<ClientInfo> mClients = new Vector<ClientInfo>();
public synchronized void addClient(ClientInfo aClientInfo) {
mClients.add(aClientInfo);
}
public synchronized void deleteClient(ClientInfo aClientInfo) {
int clientIndex = mClients.indexOf(aClientInfo);
if (clientIndex != -1)
mClients.removeElementAt(clientIndex);
}
private synchronized void sendMessageToAllClients(String aMessage)
{
for (int i = 0; i < mClients.size(); i++) {
ClientInfo infy = (ClientInfo) mClients.get(i);
infy.mClientSender.sendMessage(aMessage);
}
}
public void sendMessage(ClientInfo aClientInfo, String aMessage) {
aClientInfo.mClientSender.sendMessage(aMessage);
}
}
Class: ClientInfo
/**
*
* ClientInfo class contains information about a client, connected to the server.
*/
import java.awt.List;
import java.net.Socket;
import java.util.ArrayList;
import java.util.Vector;
public class ClientInfo
{
public int userID=-1;
public Socket mSocket = null;
public ClientListener mClientListener = null;
public ClientSender mClientSender = null;
}
Class ClientListner:
/**
* ClientListener class is purposed to listen for client messages and
* to forward them to ServerDispatcher.
*/
import java.io.*;
import java.net.*;
public class ClientListener extends Thread {
private ServerDispatcher mServerDispatcher;
private ClientInfo mClientInfo;
private BufferedReader mIn;
private String message;
private String decoded = null;
public ClientListener(ClientInfo aClientInfo,
ServerDispatcher aServerDispatcher) throws IOException {
mClientInfo = aClientInfo;
mServerDispatcher = aServerDispatcher;
Socket socket = aClientInfo.mSocket;
mIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
}
/**
* Until interrupted, reads messages from the client socket, forwards them
* to the server dispatcher and notifies the server dispatcher.
*/
public void run() {
message = "";
while (!isInterrupted()) {
try {
message = mIn.readLine();
if (message == null)
break;
try {
decoded = URLDecoder.decode(message, "UTF-8");
} catch (UnsupportedEncodingException e)
e.printStackTrace();
}
mServerDispatcher.sendMessage(mClientInfo, decoded);
}
catch (IOException e) {
break;
}
}
// Communication is broken. Interrupt both listener and sender threads
mClientInfo.mClientSender.interrupt();
mServerDispatcher.deleteClient(mClientInfo);
}
}
Class:ClientSender
/**
* Sends messages to the client. Messages are stored in a message queue. When
* the queue is empty, ClientSender falls in sleep until a new message is
* arrived in the queue. When the queue is not empty, ClientSender sends the
* messages from the queue to the client socket.
*/
import java.io.*;
import java.net.*;
import java.util.*;
public class ClientSender extends Thread
{
private Vector mMessageQueue = new Vector();
private ServerDispatcher mServerDispatcher;
private ClientInfo mClientInfo;
private PrintWriter mOut;
public ClientSender(ClientInfo aClientInfo, ServerDispatcher aServerDispatcher)
throws IOException
{
mClientInfo = aClientInfo;
mServerDispatcher = aServerDispatcher;
Socket socket = aClientInfo.mSocket;
mOut = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));
}
/**
* Adds given message to the message queue and notifies this thread
* (actually getNextMessageFromQueue method) that a message is arrived.
* sendMessage is called by other threads (ServeDispatcher).
*/
public synchronized void sendMessage(String aMessage)
{
mMessageQueue.add(aMessage);
notify();
}
/**
* #return and deletes the next message from the message queue. If the queue
* is empty, falls in sleep until notified for message arrival by sendMessage
* method.
*/
private synchronized String getNextMessageFromQueue() throws InterruptedException
{
while (mMessageQueue.size()==0)
wait();
String message = (String) mMessageQueue.get(0);
mMessageQueue.removeElementAt(0);
return message;
}
/**
* Sends given message to the client's socket.
*/
private void sendMessageToClient(String aMessage)
{
String encoded;
try {
encoded = URLEncoder.encode(aMessage,"UTF-8");
mOut.println(encoded);
mOut.flush();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
/**
* Until interrupted, reads messages from the message queue
* and sends them to the client's socket.
*/
public void run()
{
try {
while (!isInterrupted()) {
String message = getNextMessageFromQueue();
sendMessageToClient(message);
}
} catch (Exception e) {
// Commuication problem
break;
}
// Communication is broken. Interrupt both listener and sender threads
mClientInfo.mClientListener.interrupt();
mServerDispatcher.deleteClient(mClientInfo);
}
}
Ok this is the java code,now to the c# code
c# Code:
Varibales used:
private StreamWriter swSender;
private StreamReader srReceiver;
private TcpClient tcpServer;
private Thread thrMessaging;
private IPAddress ipAddr;
private bool Connected;
Function: Intelize connection:
private void InitializeConnection()
{
// Parse the IP address
string ipAdress = "XXX.XXX.XXX.XXX";
ipAddr = IPAddress.Parse(ipAdress);
// Start a new TCP connections to the chat server
tcpServer = new TcpClient();
try
{
tcpServer.Connect(ipAddr, 2002);
swSender = new StreamWriter(tcpServer.GetStream());
// Start the thread for receiving messages and further communication
thrMessaging = new Thread(new ThreadStart(ReceiveMessages));
thrMessaging.Start();
Connected=true;
}
catch (Exception e2)
{
MessageBox.Show(e2.ToString());
}
}
}
Function: ReciveMessages
private void ReceiveMessages()
{
// Receive the response from the server
srReceiver = new StreamReader(tcpServer.GetStream());
while (Connected)
{
String con = srReceiver.ReadLine();
string StringMessage = HttpUtility.UrlDecode(con, System.Text.Encoding.UTF8);
processMessage(StringMessage);
}
}
Function: proceesMessage:
private void processMessage(String p)
{
// do something with the message
}
Function sendMessage:
private void SendMessage(String p)
{
if (p != "")
{
p = HttpUtility.UrlEncode(p, System.Text.Encoding.UTF8);
swSender.WriteLine(p);
swSender.Flush();
}
}
thats it thats all you need to have communication between java server and c# client. if you have any questions dont hesitate to post them here.

Choose a protocol for encoding/sending your strings. For instance:
<length of string (4 bytes)><string data (length bytes)>
Write some Java code to send a string that follows whatever protocol you chose in #1. So using the example above, you could do something like:
public static void writeString(String string, OutputStream out) throws IOEXception {
if (string == null || "".equals(string)) {
//nothing to do
return;
}
int length = string.length();
//synchronize so that two threads don't try to write to the same stream at the same time
synchronized(out) {
out.write((length >> 24) & 0xFF);
out.write((length >> 16) & 0xFF);
out.write((length >> 8) & 0xFF);
out.write(length & 0xFF);
out.write(string.getBytes());
out.flush();
}
}
Write some equivalent code in C# to decode the strings that are being sent. It will look a lot like your Java code, except with reads instead of writes.

I think I've found a good, working solution. Using UDP sockets:
Java code
public void runJavaSocket() {
System.out.println("Java Sockets Program has started."); int i=0;
try {
DatagramSocket socket = new DatagramSocket();
System.out.println("Sending the udp socket...");
// Send the Message "HI"
socket.send(toDatagram("HI",InetAddress.getByName("127.0.0.1"),3800));
while (true) {
System.out.println("Sending hi " + i);
Thread.currentThread();
Thread.sleep(1000);
socket.send(toDatagram("HI " +
String.valueOf(i),InetAddress.getByName("127.0.0.1"),3800));
i++;
}
} catch (Exception e) {
e.printStackTrace();
}
}
public DatagramPacket toDatagram(
String s, InetAddress destIA, int destPort) {
// Deprecated in Java 1.1, but it works:
byte[] buf = new byte[s.length() + 1];
s.getBytes(0, s.length(), buf, 0);
// The correct Java 1.1 approach, but it's
// Broken (it truncates the String):
// byte[] buf = s.getBytes();
return new DatagramPacket(buf, buf.length, destIA, destPort);
}
C# code
string returnData;
byte[] receiveBytes;
//ConsoleKeyInfo cki = new ConsoleKeyInfo();
using (UdpClient udpClient =
new UdpClient(new IPEndPoint(IPAddress.Parse("127.0.0.1"), 3800)))
{
IPEndPoint remoteIpEndPoint =
new IPEndPoint(IPAddress.Parse("127.0.0.1"), 3800);
while (true)
{
receiveBytes = udpClient.Receive(ref remoteIpEndPoint);
returnData = Encoding.ASCII.GetString(receiveBytes);
Console.WriteLine(returnData);
}
}

I would just use SOAP protocol. You can use WCF on the C# side and JMS (Java messging) on the Java side. Both these technologies are built on SOAP so they can read each other's messages. They both use WSDL.