Question

For the assignment you have to do two thing

• Passing arguments when running the jar or class file
  • To run the client, command to run from CMD will be: java –jar Client.jar <server-IP> <server-Port> OR java Client <server-IP> <server-Port>
  • To run the server, command to run from CMD will be: java –jar Server.jar <server-Port> <dns-table-file-name> OR java Server <server-Port> <dns-table-file-name>

• In the server, Read the file and search for specific IP or URL based on the command received from client and reply the client with appropriate answer by adding appropriate code in the Server.java file.

.................................

import java.io.*;

import java.net.*;

public class Client {

public static void main(String[] args) throws IOException {

String serverHostname = new String ("127.0.0.1");

if (args.length > 0) {

//pass the hsotname through cmd argument

serverHostname = args[0];

}

System.out.println ("Attemping to connect to host " + serverHostname + " on

port 10007.");

Socket echoSocket = null;

PrintWriter out = null;

BufferedReader in = null;

try {

//Connect to server and open IO stream

echoSocket = new Socket(serverHostname, 10007);

out = new PrintWriter(echoSocket.getOutputStream(), true);

in = new BufferedReader(new InputStreamReader(

echoSocket.getInputStream()));

} catch (UnknownHostException e) {

System.err.println("Don't know about host: " + serverHostname);

System.exit(1);

} catch (IOException e) {

System.err.println("Couldn't get I/O for " + "the connection to: " +

serverHostname);

System.exit(1);

}

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

String userInput;

System.out.print ("input-comand: ");

while ((userInput = stdIn.readLine()) != null) {

//send to server using socket

out.println(userInput);

//read reply from server

String replyFromServer = in.readLine();

System.out.println("Answer: " + replyFromServer);

if(replyFromServer.trim().toLowerCase().equals("bye")){

break;

}

System.out.print ("input-command: ");

}

out.close();

in.close();

stdIn.close();

echoSocket.close();

}

}

--------------------------------------------

import java.net.*;

import java.io.*;

public class Server {

public static void main(String[] args) throws IOException {

ServerSocket serverSocket = null;

try {

serverSocket = new ServerSocket(10007);

}

catch (IOException e) {

System.err.println("Could not listen on port: 10007.");

System.exit(1);

}

Socket clientSocket = null;

System.out.println ("Waiting for connection ...");

try {

clientSocket = serverSocket.accept();

}

catch (IOException e) {

System.err.println("Accept failed.");

System.exit(1);

}

System.out.println ("Connection successful");

System.out.println ("Waiting for input ...");

//open IO streams

PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);

BufferedReader in = new BufferedReader(new

InputStreamReader( clientSocket.getInputStream()));

String inputLine;

//wait and read input from client. Exit when input from socket is Bye

while ((inputLine = in.readLine()) != null)

{

System.out.println ("Server: " + inputLine);

//reply back to client

out.println(inputLine);

if (inputLine.trim().toLowerCase().equals("bye"))

break;

}

//close IO streams and at the end socket

out.close();

in.close();

clientSocket.close();

serverSocket.close();

}

}

---------------------------------

DNS-table.txt

www.google.com 192.168.73.1

www.uncc.edu 192.168.73.2

www.abc.com 192.168.73.3

www.espn.com 192.168.73.4

www.cyberDNA.com 192.168.73.55

www.ccaa.uncc.edu 192.168.73.5

www.ccigrad.uncc 192.168.73.13

www.cis.uncc.edu 192.168.73.14

www.unc.edu 192.168.73.12

Answer 1

//first run Server then client....

//Java code

import java.io.*;

import java.net.*;

public class Client {

    public static void main(String[] args) throws IOException {

        String serverHostname = new String ("127.0.0.1");

        if (args.length > 0) {

//pass the hsotname through cmd argument

            serverHostname = args[0];

        }

        System.out.println ("Attemping to connect to host " + serverHostname + " on port 10007.");

        Socket echoSocket = null;

        PrintWriter out = null;

        BufferedReader in = null;

        try {

//Connect to server and open IO stream

            echoSocket = new Socket(serverHostname, 10007);

            out = new PrintWriter(echoSocket.getOutputStream(), true);

            in = new BufferedReader(new InputStreamReader(

                    echoSocket.getInputStream()));

        } catch (UnknownHostException e) {

            System.err.println("Don't know about host: " + serverHostname);

            System.exit(1);

        } catch (IOException e) {

            System.err.println("Couldn't get I/O for " + "the connection to: " +

                    serverHostname);

            System.exit(1);

        }

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

        String userInput;

        System.out.print ("input-comand: ");

        while ((userInput = stdIn.readLine()) != null) {

//send to server using socket

            out.println(userInput);

//read reply from server

            String replyFromServer = in.readLine();

            System.out.println("Answer: " + replyFromServer);

            if(replyFromServer.trim().toLowerCase().equals("bye")){

                break;

            }

            System.out.print ("input-command: ");

        }

        out.close();

        in.close();

        stdIn.close();

        echoSocket.close();

    }

}

//=================================================

import java.net.*;

import java.io.*;
import java.util.Scanner;

public class Server {

    public static void main(String[] args) throws IOException {

        ServerSocket serverSocket = null;

        try {

            serverSocket = new ServerSocket(10007);

        }

        catch (IOException e) {

            System.err.println("Could not listen on port: 10007.");

            System.exit(1);

        }

        Socket clientSocket = null;

        System.out.println ("Waiting for connection ...");

        try {

            clientSocket = serverSocket.accept();

        }

        catch (IOException e) {

            System.err.println("Accept failed.");

            System.exit(1);

        }

        System.out.println ("Connection successful");

        System.out.println ("Waiting for input ...");

//open IO streams

        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);

        BufferedReader in = new BufferedReader(new

                InputStreamReader( clientSocket.getInputStream()));

        String inputLine;

//wait and read input from client. Exit when input from socket is Bye
        Scanner scanFile = new Scanner(new File("DNS-table.txt"));
        boolean found =false;
        while ((inputLine = in.readLine()) != null)

        {

            System.out.println ("Server: " + inputLine);
            String line ="";

            if (inputLine.trim().toLowerCase().equals("bye"))
            {
                out.println(inputLine);
                break;
            }


            while (scanFile.hasNextLine())
            {
                //reply back to client
                line  = scanFile.nextLine();
                String[] tokens = line.split(" ");
                if(inputLine.equalsIgnoreCase(tokens[0]) || inputLine.equalsIgnoreCase(tokens[1])) {
                    found = true;
                    break;
                }

                else
                    found = false;

            }
            if(found) {
                out.println(line);

            }
            else {


                out.println("Not found...");
            }
        }


//close IO streams and at the end socket
        scanFile.close();
        out.close();

        in.close();

        clientSocket.close();

        serverSocket.close();

    }

}

//text file

//output

//If you need any help regarding this solution ........... please leave a comment .......... thanks