EchoUser.java

import java.io.DataInputStream;
import java.io.PrintStream;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.BufferedReader;
import java.net.Socket;
import java.net.UnknownHostException;



public class EchoUser {
    
    // The user socket
    private static Socket userSocket = null;
    // The output stream
    private static PrintStream outToServer = null;
    // The input stream
    private static BufferedReader inFromServer = null;
    
    private static BufferedReader inFromUser = null;
    
    public static void main(String[] args) {
        
        // The default port.
        int portNumber = 8000;
        // The default host.
        String host = "localhost";
      	String sentence;
        
        if (args.length < 2) {
            System.out.println("Usage: java User <host> <portNumber>\n"
                             + "Now using host=" + host + ", portNumber=" + portNumber);
        } else {
            host = args[0];
            portNumber = Integer.valueOf(args[1]).intValue();
        }
        
        /*
         * Open a socket on a given host and port. Open input and output streams.
         */
        try {
		// YOUR CODE
        	userSocket = new Socket(host,portNumber);
        	inFromUser = new BufferedReader(new InputStreamReader(System.in));
        	outToServer = new PrintStream(userSocket.getOutputStream());
        	inFromServer = new BufferedReader(new InputStreamReader(userSocket.getInputStream()));
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host " + host);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to the host "
                                   + host);
        }
        
        /*
         * If everything has been initialized then we want to send message to the
         * socket we have opened a connection to on the port portNumber.
	 * When we receive the echo, print it out.
         */
         try {
  
		// YOUR CODE
        		sentence = inFromUser.readLine();
            	outToServer.println(sentence);
            	System.out.println("echo: " + inFromServer.readLine());
                /*
                 * Close the output stream, close the input stream, close the socket.
                 */
           	outToServer.close();
            	inFromServer.close();
            	userSocket.close();
            } catch (IOException e) {
                System.err.println("IOException:  " + e);
            }
    
    }
}