bugs in client\server program - can't connect to remote server

[Siddharth Jain]

hello!

I have a client/server program in which client lets user input two
numbers and the server adds the numbers and returns the sum to client.

the problems I am having are:

1. client is not able to connect to remote server. it is only
connecting to local host.

2. if a string seperated by "non-numeric" characters (e.g. 34a2dd) is
sent, both client and server throw an uncaught exception. i need to
fix the client or server or both and give useful feedback to the user.
i need to do the error checking of user i/p so that user enters only
integers seperated by whitespace.

I am attaching my code.
I am new to java and probably don't know much.
'shall greatly appreciate your help.

thanks in advance,
sanjul

code:


// usage: java TCPAdditionServer3 <port number>
// default port is 7777
// connection to be closed by client
// this server handles only one connection

import java.io.*;
import java.net.*;
import java.lang.*;
import java.util.*;

class TCPAdditionServer3{
public static void main(String[] args)throws Exception{
String clientSentence,capitalizedSentence;
int sum=0;
String sumString = "";
InetAddress serverAddress;
int portNumber = 7777;
Socket connectionSocket = null;

try {
portNumber = Integer.parseInt(args[0]);
}
catch (Exception e) {
System.out.println(" port = 7777 (default)");
portNumber = 7777;
}

// create welcoming socket at port number specified by user or
7777 if no choice is specified by user
ServerSocket welcomeSocket=new ServerSocket(portNumber);

//server infinite loop
while(true){
try {
// wait, on welcoming socket for contact by client
connectionSocket=welcomeSocket.accept();
} catch (IOException e) {
System.out.println("Accept failed:");
System.exit(-1);
}

// create input stream, attached to socket
BufferedReader inFromClient=new BufferedReader(new
InputStreamReader(connectionSocket.getInputStream()));
// create output stream, attached to socket
DataOutputStream outToClient=new
DataOutputStream(connectionSocket.getOutputStream());

// read in line from socket
clientSentence=inFromClient.readLine();

StringTokenizer st= new StringTokenizer(clientSentence);
while(st.hasMoreTokens()) {
sum += Integer.parseInt(st.nextToken());
}

System.out.println("Waiting for connections on port " +
connectionSocket.getLocalPort() + " ... ");
System.out.println("Received connection from " +
connectionSocket.getInetAddress() + ":" +
connectionSocket.getLocalPort());

sumString = Integer.toString(sum);
clientSentence = " ";
capitalizedSentence = clientSentence + sumString + "\n";

//write out line to socket
outToClient.writeBytes(capitalizedSentence);

//connection closed by client
try {
connectionSocket.close();
System.out.println("Connection closed by client");
}
catch (IOException e) {
System.out.println(e);
}

}
}

}




code:



// usage: java TCPAdditionClient3 <server> <port>
// default port is 7777

/**
* TCPAdditionClient1.java
*
* @author Siddharth Jain
* @version 3.0
*/

/** Client Code */


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

/** this is the main class */
class TCPAdditionClient3{
public static void main(String[] args)throws Exception{

String sentence,sentc,portNumberString;
int portNumber= 7777;
String hostName = "localhost";
String modifiedSentence;
InetAddress clientAddress;
/** create input stream */
BufferedReader inFromUser1=new BufferedReader(new
InputStreamReader(System.in));

/** read arguments */
if(args.length == 2) {
hostName = args[0];
try {
portNumber = Integer.parseInt(args[1]);
System.out.println("client user i/p port number " +
portNumber);
}
catch (Exception e) {
System.out.println(" server port = 7777 (default)");
portNumber = 7777;
}
}

/** connect to server */
try{
/** create client socket, connect to server */
Socket clientSocket=new Socket(hostName,portNumber);

if (clientSocket.isConnected()== true);
{
System.out.println("Connecting to Server " +
clientSocket.getInetAddress() + ":" + clientSocket.getPort() + "..." +
"Connected");
}

/** create output stream attached to socket */
DataOutputStream outToServer=new
DataOutputStream(clientSocket.getOutputStream());
/** create input stream attached to socket */
BufferedReader inFromServer=new BufferedReader(new
InputStreamReader(clientSocket.getInputStream()));

System.out.println();
System.out.println("Enter a string of integers seperated by
non-numeric characters:");

sentence = inFromUser1.readLine();
/**send line to server */
outToServer.writeBytes(sentence+"\n");
/** read line from server */
modifiedSentence=inFromServer.readLine();
System.out.println("From Server-----> The Sum is:"+modifiedSentence);

try {
clientSocket.close();
}
catch(IOException e) {
System.out.println(e);
}

} catch(UnknownHostException e) {
System.err.println(" Don't know about host: ");
System.exit(1);
} catch(IOException e) {
System.err.println(" Couldn't get I/O for the connection");
System.exit(1);
}

}
}

 

[Thomas Fritsch]

hello! Hello!


I have a client/server program in which client lets user input two
numbers and the server adds the numbers and returns the sum to client.

the problems I am having are:

1. client is not able to connect to remote server. it is only
connecting to local host.

2. if a string seperated by "non-numeric" characters (e.g. 34a2dd) is
sent, both client and server throw an uncaught exception. i need to
fix the client or server or both and give useful feedback to the user.
i need to do the error checking of user i/p so that user enters only
integers seperated by whitespace.

I am attaching my code.
I am new to java and probably don't know much.

As you have said this: the group comp.lang.java.help is especially
well-suited for java beginners.

'shall greatly appreciate your help.

thanks in advance,
sanjul

Without having the complete exception information, we can hardly find
out where and why the error occurs. To get this information you should add
e.printStackTrace();
to the catch-clauses of your code.
After that you will get an exception stack trace with a rich amount of
information.
Some hints how to proceed:
(1) Read the javadoc of the exception class and of the
method(s) reported on the very top of the stack trace.
(2) Analyze the method of *your* code reported most near
to the top of the stack trace.
(source file-names and line-numbers are reported, too)
(3) Understand and fix the bug.
This is the most difficult part, of course ;-)
If you still don't find a solution, post your complete stack trace here,
and mark the line of your code where the exception occured.

code:

<code snipped>

Regards
Thomas