import java.net.Inet4Address;

import java.net.InetAddress;

import java.net.NetworkInterface;

import java.util.Enumeration;

import javax.servlet.http.HttpServletRequest;

public class IpUtils {

    private static final String[] HEADERS = {

        "X-Forwarded-For",

        "Proxy-Client-IP",

        "WL-Proxy-Client-IP",

        "HTTP_X_FORWARDED_FOR",

        "HTTP_X_FORWARDED",

        "HTTP_X_CLUSTER_CLIENT_IP",

        "HTTP_CLIENT_IP",

        "HTTP_FORWARDED_FOR",

        "HTTP_FORWARDED",

        "HTTP_VIA",

        "REMOTE_ADDR",

        "X-Real-IP"

    };

    /**

     * 判断ip是否为空，空返回true

     * @param ip

     * @return

     */

    public static boolean isEmptyIp(final String ip){

        return (ip == null || ip.length() == 0 || ip.trim().equals("") || "unknown".equalsIgnoreCase(ip));

    }

    /**

     * 判断ip是否不为空，不为空返回true

     * @param ip

     * @return

     */

    public static boolean isNotEmptyIp(final String ip){

        return !isEmptyIp(ip);

    }

    /***

     * 获取客户端ip地址(可以穿透代理)

     * @param request HttpServletRequest

     * @return

     */

    public static String getIpAddress(HttpServletRequest request) {

        String ip = "";

        for (String header : HEADERS) {

            ip = request.getHeader(header);

            if(isNotEmptyIp(ip)) {

                 break;

            }

        }

        if(isEmptyIp(ip)){

            ip = request.getRemoteAddr();

        }

        if(isNotEmptyIp(ip) && ip.contains(",")){

            ip = ip.split(",")[0];

        }

        if("0:0:0:0:0:0:0:1".equals(ip)){

            ip = "127.0.0.1";

        }

        return ip;

    }

    /**

     * 获取本机的局域网ip地址，兼容Linux

     * @return String

     * @throws Exception

     */

    public String getLocalHostIP() throws Exception{

        Enumeration<NetworkInterface> allNetInterfaces = NetworkInterface.getNetworkInterfaces();

        String localHostAddress = "";

        while(allNetInterfaces.hasMoreElements()){

            NetworkInterface networkInterface = allNetInterfaces.nextElement();

            Enumeration<InetAddress> address = networkInterface.getInetAddresses();

            while(address.hasMoreElements()){

                InetAddress inetAddress = address.nextElement();

                if(inetAddress != null && inetAddress instanceof Inet4Address){

                    localHostAddress = inetAddress.getHostAddress();

                }

            }

        }

        return localHostAddress;

    }

}