Algorithm
Start the UDP chat program
Import the package java.net.*;
Declare the datagram socket ,datagrampacket,BufferedReader,InetAddress.
Start the main function
In the main function using while loop it perform the loop until str.equals is STOP
There important while loop function are
clientsocket = new DatagramSocket(cport);
dp = new DatagramPacket(buf, buf.length);
dis = new BufferedReader(new
InputStreamReader(System.in));
ia = InetAddress.getLocalHost(); f it is stop then break the while loop
Terminate the UDP client program
source code java programming UDP Chat server
import java.io.*;
import java.net.*;
class UDPServer
{
public static DatagramSocket serversocket;
public static DatagramPacket dp;
public static BufferedReader dis;
public static InetAddress ia;
public static byte buf[] = new byte[1024];
public static int cport = 789,sport=790;
public static void main(String[] a) throws IOException
{
serversocket = new DatagramSocket(sport);
dp = new DatagramPacket(buf,buf.length);
dis = new BufferedReader
(new InputStreamReader(System.in));
ia = InetAddress.getLocalHost();
System.out.println("Server is Running...");
while(true)
{
serversocket.receive(dp);
String str = new String(dp.getData(), 0,
dp.getLength());
if(str.equals("STOP"))
{
System.out.println("Terminated...");
break;
}
System.out.println("Client: " + str);
String str1 = new String(dis.readLine());
buf = str1.getBytes();
serversocket.send(new
DatagramPacket(buf,str1.length(), ia, cport));
}
}
}
Output:-
C:\IPLAB>javac UDPServer.java
C:\IPLAB>java UDPServer
Server is Running...
Client: Hello
Welcome
Terminated...
source code java programming UDP Chat Client
import java.io.*;
import java.net.*;
class UDPClient
{
public static DatagramSocket clientsocket;
public static DatagramPacket dp;
public static BufferedReader dis;
public static InetAddress ia;
public static byte buf[] = new byte[1024];
public static int cport = 789, sport = 790;
public static void main(String[] a) throws IOException
{
clientsocket = new DatagramSocket(cport);
dp = new DatagramPacket(buf, buf.length);
dis = new BufferedReader(new
InputStreamReader(System.in));
ia = InetAddress.getLocalHost();
System.out.println("Client is Running... Type 'STOP'
to Quit");
while(true)
{
String str = new String(dis.readLine());
buf = str.getBytes();
if(str.equals("STOP"))
{
System.out.println("Terminated...");
clientsocket.send(new
DatagramPacket(buf,str.length(), ia,
sport));
break;
}
clientsocket.send(new DatagramPacket(buf,
str.length(), ia, sport));
clientsocket.receive(dp);
String str2 = new String(dp.getData(), 0,
dp.getLength());
System.out.println("Server: " + str2);
}
}
}
Output UDP Chat Client
C:\IPLAB>javac UDPClient.java
C:\IPLAB>java UDPClient
Client is Running... Type ‘STOP’ to Quit
Hello
Server: Welcome
STOP
Terminated...
BB / REC - 41
Object: To write a java program for creating Simple chat application with datagram sockets and datagram packets. CS1404 INTERNET PROGRAMMING LABORATORY.
