DatagramSocket 与 UDP

简单的DatagramSocket demo

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


public class UdpRecv {

    public static void main(String[] args) throws IOException{

        DatagramSocket ds = new DatagramSocket(5000);
        byte[] buf = new byte[1024];
        DatagramPacket dp = new DatagramPacket(buf,1024);
        /*
         * Receives a datagram packet from this socket.
         * When this method returns, the DatagramPacket's buffer is filled with the data received.
         * The datagram packet also contains the sender's IP address, and the port number on the sender's machine.
         * This method blocks until a datagram is received.
         */
        ds.receive(dp);
        String userinput = new String(dp.getData(),0,dp.getLength());
        String strRecv = new String(dp.getData(),0,dp.getLength()) + " from "+
        dp.getAddress().getHostAddress()+":"+dp.getPort();
        System.out.println(strRecv);
        ds.close();


    }

}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;

public class UdpSend {

    public static void main(String[] args) throws IOException{
        while(true){
            DatagramSocket ds = new DatagramSocket();
            String str = "hello socket!";
            BufferedReader userinput = new BufferedReader(new InputStreamReader(System.in));
            str += userinput.readLine();
            DatagramPacket dp = new DatagramPacket(str.getBytes(),str.length(),
                    InetAddress.getByName("127.0.0.1"),5000);

            ds.send(dp);
            ds.close();
        }


    }
}

谢谢访问！