Question

So I wrote a simple Socket program that send message from Client to Server program and wanted to know what is the proper procedure to go about testing this? Both my Client and Server machines are running on Ubuntu 12.04 and I’m remote connecting to both of them.

For my Client code when I instantiate the client socket (testSocket) do I use its IP Address and Port number or Servers IP Address and Port number?

Here is the Code for Client:

public static void main(String[] args) throws UnknownHostException, IOException 
{
    Socket testSocket = null;
    DataOutputStream os = null;
    DataInputStream is = null;

    try
    {
        testSocket = new Socket("192.168.0.104", 5932);
        os = new DataOutputStream(testSocket.getOutputStream());
        is = new DataInputStream(testSocket.getInputStream());
    }
    catch (UnknownHostException e)
    {
        System.err.println("Couldn't find Host");
    }
    catch (IOException e)
    {
        System.err.println("Couldn't get I/O connection");
    }

    if (testSocket != null && os != null && is != null)
    {
        try
        {
            os.writeBytes("Hello Server!\n");

            os.close();
            is.close();
            testSocket.close();

        }

        catch (UnknownHostException e)
        {
            System.err.println("Host not found");
        }
        catch (IOException e)
        {
            System.err.println("I/O Error");
        }
    }

}

Here is the code for Server:

public static void main(String[] args) 
{
    String line = new String() ;


    try
    {
       ServerSocket echoServer = new ServerSocket(5932);

       Socket clientSocket = echoServer.accept();

      DataInputStream  is = new DataInputStream(clientSocket.getInputStream());
      PrintStream os = new PrintStream(clientSocket.getOutputStream());

           while (true) 
           {
             line = is.readLine();
             os.println(line); 
           }
    }
    catch (IOException e)
    {
        System.out.println(e.getMessage());
    }

}

I’m new to Sockets and not sure what I’m supposed be seeing. I compiled both programs in terminal fine but not sure which one should I be running first or do they need to be started simultaneously?

Thanks

Answer 1

Your server is running in a infinite loop. Avoid that.
You have to restart your computer.

while (true) 
           {
             line = is.readLine();
             os.println(line); 
           }

try

while (!line.equals("Hello Server!")) 
           {
             line = is.readLine();
             os.println(line); 
           }

Run the server first. echoServer.accept(); waits for a connection. When it gets the first connection,