TCP CHAT APPLICATION

NAME: SATHIYA A K
ROLL NO: 21CS149

CODE:

FILE: TCPClient.java

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

public class TCPClient {

public static void main(String[] args) {
String serverAddress = "localhost"; // Server's IP address or hostname
int serverPort = 8080; // Port number the server is listening on

try {
// Create a socket to connect to the server
Socket socket = new Socket(serverAddress, serverPort);

// Set up input and output streams for communication

BufferedReader in = new BufferedReader(new
InputStreamReader(socket.getInputStream()));
PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

// Send a message to the server

out.println("Hello, Server!");

// Receive and print the response from the server

String serverResponse = in.readLine();
System.out.println("Received from server: " + serverResponse);

// Close the socket and streams

in.close();
out.close();
socket.close();

} catch (IOException e) {
e.printStackTrace();
}
}
}
FILE:TCPServer.java

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

public class TCPServer {

public static void main(String[] args) {
int port = 8080; // Port number to listen on
try {
// Create a server socket
ServerSocket serverSocket = new ServerSocket(port);
System.out.println("Server is listening on port " + port);

// Wait for a client to connect

Socket clientSocket = serverSocket.accept();
System.out.println("Client connected from " +
clientSocket.getInetAddress().getHostAddress());

// Set up input and output streams for communication

BufferedReader in = new BufferedReader(new
InputStreamReader(clientSocket.getInputStream()));
PrintWriter out = new PrintWriter(clientSocket.getOutputStream(),
true);

// Read data from the client

String clientMessage = in.readLine();
System.out.println("Received from client: " + clientMessage);

String responseMessage = "Hello, Client!"; // Change this message

as needed

// Send a reply back to the client

out.println(responseMessage);
System.out.println("Sent to client: " + responseMessage);

// Close the sockets and streams

in.close();
out.close();
clientSocket.close();
serverSocket.close();

} catch (IOException e) {
e.printStackTrace();
}
}
}
OUTPUT:

UDP CHAT APPLICATION

CODE:
import java.io.*;
import java.net.*;

public class UDPClient {

public static void main(String[] args) {
DatagramSocket clientSocket = null;
try {
// Create a UDP socket
clientSocket = new DatagramSocket();
InetAddress serverAddress = InetAddress.getByName("127.0.0.1");
int serverPort = 9876;
BufferedReader userInput = new BufferedReader(new
InputStreamReader(System.in));

while (true) {
System.out.print("Enter a message to send to the server (or
'exit' to quit): ");
String message = userInput.readLine();

if (message.equals("exit")) {
break;
}

byte[] sendData = message.getBytes();

DatagramPacket sendPacket = new DatagramPacket(sendData,
sendData.length, serverAddress, serverPort);
clientSocket.send(sendPacket);

byte[] receiveData = new byte[1024];

DatagramPacket receivePacket = new DatagramPacket(receiveData,
receiveData.length);
clientSocket.receive(receivePacket);
String serverReply = new String(receivePacket.getData(), 0,
receivePacket.getLength());
System.out.println("Received from server: " + serverReply);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (clientSocket != null && !clientSocket.isClosed()) {
clientSocket.close();
}
}
}
}
import java.io.*;
import java.net.*;

public class UDPServer {

public static void main(String[] args) {
DatagramSocket serverSocket = null;
try {
// Create a UDP socket
serverSocket = new DatagramSocket(9876);
byte[] receiveData = new byte[1024];
System.out.println("Server is waiting for data...");
while (true) {
DatagramPacket receivePacket = new DatagramPacket(receiveData,
receiveData.length);
serverSocket.receive(receivePacket);
String clientMessage = new String(receivePacket.getData(), 0,
receivePacket.getLength());
InetAddress clientAddress = receivePacket.getAddress();
int clientPort = receivePacket.getPort();

System.out.println("Received from client at " + clientAddress

+ ":" + clientPort + ": " + clientMessage);

// Process the received data (you can add your logic here)

// Send a reply back to the client

String serverReply = "Hello from the server!";
byte[] sendData = serverReply.getBytes();
DatagramPacket sendPacket = new DatagramPacket(sendData,
sendData.length, clientAddress, clientPort);
serverSocket.send(sendPacket);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (serverSocket != null && !serverSocket.isClosed()) {
serverSocket.close();
}
}
}
}

OUTPUT: