CODEWITHSUNDEEP
javasocketstcp
Guillermo Alvarez
Guillermo Alvarez

Reputation: 1775

How to test sample TCP Socket program

I have a sample TCP client and server application that I want to run but I am not sure how to run them. It says I need to compile the client program in one host and the server application in another but I have no idea how to do this when I just have one computer. I know this is very simple but I need a little help to get me started.

Here is the sample TCP Server application:

import java.io.*; 
import java.net.*;

class TCPServer {

public static void main(String argv[]) throws Exception 
{ 
  String clientSentence; 
  String capitalizedSentence;

  ServerSocket welcomeSocket = new ServerSocket(6790); 

  while(true) { 

               Socket connectionSocket = welcomeSocket.accept();

       BufferedReader inFromClient = 
         new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));

       DataOutputStream  outToClient = 
         new DataOutputStream(connectionSocket.getOutputStream());

       clientSentence = inFromClient.readLine();

       capitalizedSentence = clientSentence.toUpperCase() + '\n';

       outToClient.writeBytes(capitalizedSentence); 
    } 
} 
}

Here is the sample TCPClient application

import java.io.*; 
import java.net.*; 
class TCPClient {

    public static void main(String argv[]) throws Exception 
    { 
        String sentence; 
        String modifiedSentence;

        BufferedReader inFromUser = 
          new BufferedReader(new InputStreamReader(System.in));

        Socket clientSocket = new Socket("10.0.1.2", 6790);

        DataOutputStream outToServer = 
          new DataOutputStream(clientSocket.getOutputStream());

        BufferedReader inFromServer = 
          new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));

        sentence = inFromUser.readLine();

        outToServer.writeBytes(sentence + '\n');

        modifiedSentence = inFromServer.readLine();

        System.out.println("FROM SERVER: " + modifiedSentence);

        clientSocket.close(); 
                   
    } 
}

Is something off here?

Here is exactly what I do

step1
(source: skitch.com)

step2
(source: skitch.com)

This is the first time I use Eclipse so I could be doing something wrong there. I normally use DrJava but that didn't let me run both at the same time for some reason.

Upvotes: 2

Views: 15879

Answers (2)

Ruskin Janowski
Ruskin Janowski

Reputation: 171

For anyone using this code, I just stepped through the program and see that the connection is established successfully (if you change to the appropriate IP such as 'localhost'). However both the TCPServer and the TCPClient do a readLine first so they are both stuck waiting for input which never comes. Change one of them to write something first.

Upvotes: 0

Greg Hewgill
Greg Hewgill

Reputation: 992757

Almost any socket program can run both halves on the same computer. Just run the server in one window, the client in another, and specify the connection address 127.0.0.1 (which means localhost, your own computer).

Upvotes: 4

Related Questions