import java.net.InetAddress;
import java.net.UnknownHostException;

import javax.servlet.http.HttpServletRequest;

/**
 * 功能說明：IP地址工具
 * 
 * @author LZG
 *
 */
public class IPAddressUtil {

    /**
     * 從發的request請求的頭資訊裡獲取客戶端IP地址
     * @param request
     * @return ip 客戶端IP地址
     */

    public static
 
 String getClientIPAddress(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();
        }

        /*
         * 對於通過多個代理的情況，第一個IP為客戶端真實IP,多個IP按照','分割 "***.***.***.***".length() = 15
         */
 

        if (ip != null && ip.length() > 15) {
            if (ip.indexOf(",") > 0) {
                ip = ip.substring(0, ip.indexOf(","));
            }
        }

        return ip;
    }

    /**
     * 獲取本地機器IP地址
     * @return 本地IP地址
     */
    public static String getLocalIPAddress() {

        InetAddress inet = null;

        try {
            inet = InetAddress.getLocalHost();
        } catch (UnknownHostException e) {
            e.printStackTrace();
        }

        return inet.getHostAddress();
    }

    //測試使用
    public static void main(String[] args) {
         System.out.println(getLocalIPAddress());
    }

}