import java.net.InetAddress;
import java.net.UnknownHostException;public class IPDemo {public static void main(String[] args) throws UnknownHostException {//        InetAddress i = InetAddress.getLocalHost();获取本地信息
//      System.out.println(i);  InetAddress i = InetAddress.getByName("www.baidu.com");System.out.println(i.getHostAddress());System.out.println(i.getHostName());}
}

import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;class UdpSend{//1.创建socket服务//2.传输数据，并打包//3.发送//4.关闭资源public static void main(String[] args) throws Exception {//1.创建socket服务DatagramSocket socket = new DatagramSocket(10000);//指定发送器端口//2.传输数据，并打包byte[] buf = "udp hello".getBytes();DatagramPacket packet = new DatagramPacket(buf, buf.length, InetAddress.getByName("localhost"), 8888);//指定应用程序端口//发送socket.send(packet);//关闭资源socket.close();System.out.println("over");}
}
/** 1.创建服务socket，并监听端口* 2.定义一个数据包，用来接受数据包* 3.用socket服务接受的数据保存到，数据包中* 4.取出数据* 5.关闭资源*/
class UdpRece{public static void main(String[] args)  throws Exception {DatagramSocket ds = new DatagramSocket(8888);//指定应用程序的端口byte[] buf = new byte[1024]; DatagramPacket dp = new DatagramPacket(buf, buf.length);ds.receive(dp);String ip = dp.getAddress().getHostAddress();int port = dp.getPort();String data = new String(dp.getData(),0,dp.getLength());System.out.println(ip+":"+port+":"+data);ds.close();}
}public class UdpDemo {public static void main(String[] args) {}
}

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;class Send{public static void main(String[] args) throws Exception {DatagramSocket socket = new DatagramSocket();BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));String line =null;while((line = reader.readLine())!=null){if("886".equals(line)){break;}byte[] buf = line.getBytes();DatagramPacket dp = new DatagramPacket(buf,buf.length,InetAddress.getByName("127.0.0.1"),8888);socket.send(dp);}reader.close();socket.close();}
}
class Rece{@SuppressWarnings("resource")public static void main(String[] args) throws Exception {DatagramSocket socket = new DatagramSocket(8888);while(true){byte[] buf = new byte[1024];DatagramPacket dp =new DatagramPacket(buf, buf.length);socket.receive(dp);String data = new String(dp.getData(),0,dp.getLength());String ip = dp.getAddress().getHostAddress();int port = dp.getPort();System.out.println(ip+":"+port+":"+data);}}
}
public class UdpDemo2 {public static void main(String[] args) {}
}