Question

The following Client side Java code can send a message to the server side via UDP socket. The client side Java code and the server side Java code are running in two different hosts respectively. The server side host name is “MyFileServer”. The server side receives the message and converts all the letters in the message received to uppercase, then sends the modified message back to the client side. Please read the code carefully, and fill out the blanks with appropriate code to make them work.

===Client Side Java code below======

import java.io.*;

import java.net.*;

class UDPClient {

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

    {

      DatagramSocket clientSocket = new __________;

      InetAddress IPAddress = InetAddress.getByName("________");

      byte[] sendData = new byte[1024];

      byte[] receiveData = new byte[1024];

      String sentence = “This is a Test for cpsc5157U class”;

________ = sentence.getBytes();    

    DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.______, IPAddress, _____);

      clientSocket.______;

      DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);

      clientSocket.receive(________);

      String modifiedSentence = new String(receivePacket.getData());

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

      clientSocket.close();

      }

}

=======End of Client Side Code ===========

==== Server Side Java Code below===========

import java.io.*;

import java.net.*;

class UDPServer {

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

    {

      DatagramSocket serverSocket = new ____________(34926);

      byte[] receiveData = new byte[1024];

      byte[] sendData = new byte[1024];

      while(true) {

          DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);

          serverSocket.receive(receivePacket);

          String sentence = new String(receivePacket.getData());

          InetAddress MyAddress = receivePacket.getAddress();

          int port = receivePacket.getPort();

          String capitalizedSentence = sentence.toUpperCase();

          sendData = capitalizedSentence.getBytes();

          DatagramPacket sendPacket = new DatagramPacket(______, sendData.length, _______, port);

          serverSocket.send(sendPacket);

       }

     }

}

========= End of Server Side Java Code============

Answer 1

If you have any problem with the code feel free to comment.

Client

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

class UDPClient {

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

       DatagramSocket clientSocket = new DatagramSocket();

       InetAddress IPAddress = InetAddress.getByName(null);

       byte[] sendData = new byte[1024];

       byte[] receiveData = new byte[1024];

       String sentence = "This is a Test for cpsc5157U class";

       sendData = sentence.getBytes();

       DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, 34926);

       clientSocket.send(sendPacket);

       DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);

       clientSocket.receive(receivePacket);

       String modifiedSentence = new String(receivePacket.getData());

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

       clientSocket.close();

   }

}

Server

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

class UDPServer {

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

       DatagramSocket serverSocket = new DatagramSocket(34926);

       byte[] receiveData = new byte[1024];

       byte[] sendData = new byte[1024];

       while (true) {

           DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);

           serverSocket.receive(receivePacket);

           String sentence = new String(receivePacket.getData());

           InetAddress MyAddress = receivePacket.getAddress();

           int port = receivePacket.getPort();

           String capitalizedSentence = sentence.toUpperCase();

           sendData = capitalizedSentence.getBytes();

           DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, MyAddress, port);

           serverSocket.send(sendPacket);

       }

   }

}

Output

FROM SERVER: THIS IS A TEST FOR CPSC5157U CLASS