Question

i am trying to wrire a word and change it to capital letters using client-server. im not able to write any words when i run the file in netbeans or command promot. is it something with my code?

/*

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*/

package assignment3retake;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import java.net.Socket;

/**

*

*/

public class Capitalizer implements Runnable{

   

    private Socket socket;

   

     Capitalizer(Socket socket) {

        this.socket = socket;

    }

   

    @Override

    public void run() {

        System.out.println("Connected: " + socket);

        try {

            // TODO Create socket reader

            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));

            // TODO Create socket writer

            PrintWriter out = new PrintWriter(socket.getOutputStream());

            // Read from the socket and using a loop, change the case to upper and write to the socket

            String sentence = in.readLine();

            while(sentence != null){              

                    sentence.toUpperCase();

                    System.out.println(sentence + in.readLine());

            }

            in.close();

            out.close();

        } catch (Exception e) {

            System.out.println("Error:" + socket);

        } finally {

            try {

                socket.close();

               

            } catch (IOException e) {

            }

            System.out.println("Closed: " + socket);

        }

    }

   

}

package assignment3retake;

import java.net.*;

import java.io.*;

import java.io.IOException;

import java.net.Socket;

/**

*

*/

public class Client {

        public static void main(String[] args){

            try{

                //connect to server

                Socket sock = new Socket("127.0.0.1",59898);

               

                PrintStream sout = new PrintStream(sock.getOutputStream());

               // InputStream in = sock.getInputStream();

                BufferedReader bin = new BufferedReader(new InputStreamReader(sock.getInputStream()));

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

                String sentence;

               

                 while(true){

                   System.out.flush();

                   sentence = uin.readLine();

                  if(sentence == null)break;

                   sout.println(sentence);

                   sentence = bin.readLine();

                      

                   if(sentence == null){

                       //close the socket

                       sock.close();

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

                       break;

                   }

                   System.out.println(sentence);                 

                }

            }catch(IOException ioe){

                System.err.println(ioe);

            }

           

        }

}

/*

* To change this license header, choose License Headers in Project Properties.

* To change this template file, choose Tools | Templates

* and open the template in the editor.

*/

package assignment3retake;

import java.net.ServerSocket;

import java.net.Socket;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

/**

*

*/

public class Server {

    /**

     * @param args the command line arguments

     */

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

        // TODO code application logic here

        try (ServerSocket listener = new ServerSocket(59898)) {

            System.out.println("The capitalization server is running...");

           // TODO Create a thread pool of 10 clients

            ExecutorService pool = Executors.newFixedThreadPool(10);

            while (true) {

                Socket s = listener.accept();

                // TODO call pool.execute() with a parameter which is an instance of the Capitalizer class

                pool.execute(new Capitalizer(s));

            }

        }

    }

}

Answer 1

I have change your code. I have used DataInputStream and DataOutputStream to recieve and send data from client to server.

Code is 100% runnable.

Run Server.java at first and then client

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

Capitalizer.java

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.DataInputStream;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintWriter;

import java.net.Socket;

/**
*
*
*
*/
public class Capitalizer implements Runnable {

private Socket socket;

Capitalizer(Socket socket) {

this.socket = socket;

}

@Override

public void run() {

System.out.println("Connected: " + socket);

try {

DataInputStream in = new DataInputStream(
new BufferedInputStream(socket.getInputStream()));
  
String sentence = in.readUTF();
  
// reads message from client until "Over" is sent
while (sentence!=null)
{
try
{
sentence=sentence.toUpperCase();
System.out.println(sentence);
sentence = in.readUTF();
  
  
}
catch(IOException i)
{
System.out.println(i);
}
}
System.out.println("Closing connection");
  
// close connection

in.close();
  

} catch (Exception e) {

System.out.println("Error:" + socket);

} finally {

try {

socket.close();

} catch (IOException e) {

}

System.out.println("Closed: " + socket);

}

}

}

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

Client.java

import java.net.*;

import java.io.*;

import java.io.IOException;

import java.net.Socket;

/**
*
*
*
*/
public class Client {

public static void main(String[] args) {

try {

//connect to server
Socket sock = new Socket("127.0.0.1", 59898);

// takes input from terminal
DataInputStream input = new DataInputStream(System.in);

// sends output to the socket
DataOutputStream out = new DataOutputStream(sock.getOutputStream());

String sentence;

while (true) {

System.out.flush();

sentence = input.readLine();
out.writeUTF(sentence);

if (sentence == null) {

//close the socket
sock.close();

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

break;

}

System.out.println(sentence);

}

} catch (IOException ioe) {

System.err.println(ioe);

}

}

}
----------------------------------------------------------------------------------------------------------------------------------------------

Server.java

import java.net.ServerSocket;

import java.net.Socket;

import java.util.concurrent.ExecutorService;

import java.util.concurrent.Executors;

/**

*

*/

public class Server {

/**

* @param args the command line arguments

*/

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

// TODO code application logic here

try (ServerSocket listener = new ServerSocket(59898)) {

System.out.println("The capitalization server is running...");

// TODO Create a thread pool of 10 clients

ExecutorService pool = Executors.newFixedThreadPool(10);

while (true) {

Socket s = listener.accept();

// TODO call pool.execute() with a parameter which is an instance of the Capitalizer class

pool.execute(new Capitalizer(s));

}

}

}

}

--------------------------------------------------------------------------OUTPUT---------------------------------------------------------------

Server Side

Client 1

Client 2