package?demostrator;

import?java.io.IOException;
import?java.net.DatagramPacket;
import?java.net.DatagramSocket;

public?class?UDPserver?{
	public?static?void?main(String[]?args)?throws?IOException?{
		DatagramSocket?socket?=?new?DatagramSocket(8888);
		
		byte[]?data?=?new?byte[1024];
		DatagramPacket?packet?=?new?DatagramPacket(data,?data.length);
		
		System.out.println("***Server?will?be?start!***");
		
		while?(true)?{
			socket.receive(packet);
			
			ServerThread?thread?=?new?ServerThread(packet,socket);
			thread.start();
		}

	}
}

package?demostrator;
import?java.io.IOException;
import?java.net.DatagramPacket;
import?java.net.DatagramSocket;
import?java.net.InetAddress;
public?class?ServerThread?extends?Thread?{
DatagramPacket?packet?=?null;
DatagramSocket?socket?=?null;
ServerThread(DatagramPacket?packet,DatagramSocket?socket){
this.packet?=?packet;
this.socket?=?socket;
}
public?void?run(){
String?info?=?new?String(packet.getData());
//output?info?from?client
System.out.println("i?am?server,client?say:?"+info);
InetAddress?clientAddress?=?packet.getAddress();
int?port?=?packet.getPort();
byte[]?data1=?"Welcome?to?server!~".getBytes();
DatagramPacket?packet1?=?new?DatagramPacket(data1,?data1.length,?clientAddress,?port);
try?{
socket.send(packet1);
}?catch?(IOException?e)?{
//?TODO?Auto-generated?catch?block
e.printStackTrace();
}
}
}


package?demostrator;

import?java.io.IOException;
import?java.net.DatagramPacket;
import?java.net.DatagramSocket;
import?java.net.InetAddress;

public?class?UDPclient?{
	public?static?void?main(String[]?args)?throws?IOException?{
		//get?InetAddress?of?server
		InetAddress?add?=?InetAddress.getByName("localhost");
		int?port?=?8888;
		byte[]?info?=?"usearname:wujun;?password:416471".getBytes();
		
		DatagramPacket?packet?=?new?DatagramPacket(info,info.length,add,port);
		DatagramSocket?socket?=?new?DatagramSocket();
		
		socket.send(packet);
		
		//receive?server?infomation
		byte[]?serverMsg?=?new?byte[1024];
		DatagramPacket?packet1?=?new?DatagramPacket(serverMsg,?0,?serverMsg.length);
		socket.receive(packet1);
		
		String?strServer?=?new?String(serverMsg);
		System.out.println("Server?say:"+strServer);
		socket.close();
	}

}