import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.Enumeration;

/**
 *
 * @anthor leo
 * @date 2016年6月27日下午12:40:14
 * @description
 *
 **/

public class Main {

	public static void main(String[] args) throws SocketException {
		System.out.println(Main.getRealIp());
	}

	public static String getRealIp() throws SocketException {
		String localip = null;// 本地IP，如果沒有配置外網IP則返回它
		String netip = null;// 外網IP

		Enumeration<NetworkInterface> netInterfaces = NetworkInterface.getNetworkInterfaces();
		InetAddress ip = null;
		boolean finded = false;// 是否找到外網IP
		while (netInterfaces.hasMoreElements() && !finded) {
			NetworkInterface ni = netInterfaces.nextElement();
			Enumeration<InetAddress> address = ni.getInetAddresses();
			while (address.hasMoreElements()) {
				ip = address.nextElement();
				if (!ip.isSiteLocalAddress() && !ip.isLoopbackAddress() && ip.getHostAddress().indexOf(":") == -1) {// 外網IP
					netip = ip.getHostAddress();
					finded = true;
					break;
				} else if (ip.isSiteLocalAddress() && !ip.isLoopbackAddress()
						&& ip.getHostAddress().indexOf(":") == -1) {// 內網IP
					localip = ip.getHostAddress();
				}
			}
		}

		if (netip != null && !"".equals(netip)) {
			return netip;
		} else {
			return localip;
		}
	}
}