InetAddress

import java.net.*;
class  InetAddressDemo
{
	public static void main(String[] args)throws Exception 
	{

		InetAddress ipObj = InetAddress.getByName("127.0.0.1");
		
		System.out.println("hostName:"+ipObj.getHostName());


		InetAddress ipObj1 = InetAddress.getByName("www.sina.com.cn");		
		System.out.println("ip:"+ipObj1.getHostAddress());
		System.out.println("localip:"+InetAddress.getLocalHost());
	}
}