udpclient2.java

this a client server programming that send a message to server and acknowledgement from the server.

package helloworld;

// UDPClient.java
// A client program implementing UDP socket
import java.net.*; 
import java.io.*; 

public class UDPClient2{
    public static void main(String args[])
    {//args give message contents and server hostname 
		DatagramSocket aSocket = null;
		try { 
		    int serverPort = 6880; 
                    String ip = "202.185.107.175";
                    String message = "Hello World";
                    InetAddress aHost = InetAddress.getByName(ip);
                    
                    System.out.println("start client...");
		    aSocket = new DatagramSocket(); 
		    		    
		    DatagramPacket request = 
	                new DatagramPacket(message.getBytes(), message.length(), aHost, serverPort); 
		    //send a message to server
		    aSocket.send(request);
		    System.out.println("send to    : " + request.getAddress() + ":" + 
		    	request.getPort() + " message - " + new String(request.getData()).trim()); 
		    byte[] buffer = new byte[1000]; 
		    DatagramPacket reply = new DatagramPacket(buffer, buffer.length);
		    System.out.println("waiting server reply ...");
		    //listening reply from server
		    aSocket.receive(reply); 
		    System.out.println("reply from : " + reply.getAddress() + ":" + 
		    	reply.getPort() + " message - " + new String(reply.getData()).trim()); 
		    //close socket
		    aSocket.close();
		} 
		catch (SocketException e){
		    System.out.println("Socket: " + e.getMessage());
		}
	        catch (IOException e){
		    System.out.println("IO: " + e.getMessage());
		}
		finally{ if(aSocket != null) aSocket.close();}
}
}