Java中UDP的简单使用

服务端：

/**
* Created by cuboo on 2016/10/12.
*/
import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;
import java.net.UnknownHostException;

public class udpserver {
private static DatagramSocket socket;
private DatagramPacket packet;
private static int port = 8001;
public static void main(String[] args) {
udpserver server = new udpserver();
try {
socket = new DatagramSocket(port);
while (true){

DatagramPacket packet = server.receiveMessage(socket);
server.sendMessage(socket,packet);
}

} catch (SocketException e) {
e.printStackTrace();
}

}
public void sendMessage(DatagramSocket socket,DatagramPacket receive_packet){
try {
byte[] datas = "hello this is udpserver echo".getBytes();
//receive_packet接受到的客服端的ip地址和端口
packet = new DatagramPacket(datas,datas.length,receive_packet.getAddress(),receive_packet.getPort());
socket.send(packet);

} catch (UnknownHostException e) {
e.printStackTrace();
} catch (SocketException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public DatagramPacket receiveMessage(DatagramSocket socket){
try {
byte[] data = new byte[100];
packet = new DatagramPacket(data,data.length);
socket.receive(packet);
System.out.println(new String(packet.getData(),0,packet.getLength()));

} catch (IOException e) {
e.printStackTrace();
}
//返回接受到的客服端的ip地址和端口
return packet;
}
}


客户端：
import java.io.IOException;
import java.net.*;

/**
* Created by cuboo on 2016/10/12.
*/
public class udpclient {
private static DatagramSocket socket;
private DatagramPacket packet;
private int port = 8001;

public static void main(String agrs[]){
udpclient client = new udpclient();
try {
socket = new DatagramSocket();
while (true){
client.sendMessage();
client.receivMessage();
}
} catch (SocketException e) {
e.printStackTrace();
}

}
public void sendMessage(){
try {
byte[] datas = "hello this is client echo".getBytes();
packet = new DatagramPacket(datas,datas.length, InetAddress.getLocalHost(),port);
socket.send(packet);

} catch (SocketException e) {
e.printStackTrace();
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

public void receivMessage(){
try {
byte[] data = new byte[100];
packet = new DatagramPacket(data,data.length);
socket.receive(packet);
System.out.println(new String(packet.getData(),0,packet.getLength()));

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