IPUtil工具类，获取本机、远程IP

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

import javax.servlet.http.HttpServletRequest;

/**
 * IP工具类
 * @author geeksun
 * 2011-9-23
 */
public class IpUtil {

    /**
     * @param 获取远程IP
     * @return IP Address
     */
    public static String getIpAddrByRequest(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        return ip;
    }

    /**
     * @return 获取本机IP
     * @throws SocketException
     */
    public static String getRealIp() throws SocketException {
        String localip = null;// 本地IP，如果没有配置外网IP则返回它
        String netip = null;// 外网IP

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

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

}