网络通信三要素：IP、端口、协议

import java.net.InetAddress;
import java.net.UnknownHostException;
/*
 * 网络通信三要素：IP、端口、协议
 */
public class IPDemo {
   public static void main(String[] args) {
  try {
InetAddress i=InetAddress.getLocalHost();
System.out.println("address= "+i.getHostAddress());//address= 18.218.27.0
System.out.println("address= "+i.getHostName());//address= Len-P
System.out.println(i);//Lenovo-PC/18.218.27.0

InetAddress ia=InetAddress.getByName("www.baidu.com");//主机名
System.out.println("address= "+ia.getHostAddress());
System.out.println("address= "+ia.getHostName());


} catch (UnknownHostException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}