datagramserver.java

SSD8练习3 传上去大家参考参考 研究研究

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

//DatagramServer
public class DatagramServer{

	//UDP port to which service is bound
	public static final int SERVICE_PORT = 7;

	//Max size of packet
	public static final int SIZE = 1;

	//socket used for reading and writing UDP packets
	private DatagramSocket socket;

	public DatagramServer(){

		try{

			//Bind to the specified UDP port, to listen for incoming data packets
			socket = new DatagramSocket(SERVICE_PORT);
			System.out.println("Server active on port " + socket.getLocalPort());
		}catch(Exception e){

			System.err.println("Unable to bind port");
		}
	}

	public void serviceClients(){

		//Creat a buffer large enough for incoming packets
		byte[] buffer = new byte[SIZE];

		for(;;){

			try{

				//Creat a DatagramPacket for reading UDP packets
				DatagramPacket packet = new DatagramPacket(buffer, SIZE);

				//Receive incoing pakcets
				socket.receive(packet);

				System.out.println("Packet receive from " + packet.getAddress() + ":"+ packet.getPort());

				//Echo the packet back - address and port are already set for us!
				socket.send(packet);
			}catch(IOException ioe){

				System.err.println("Error: "+ ioe);
			}
		}
	}
	public static void main(String args[]){

		DatagramServer server = new DatagramServer();
		server.serviceClients();
	}
}