import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 * 獲取IP工具類
 * @create 2017-03-29
 */
public class IPUtils {
    private static Logger logger = LoggerFactory.getLogger(IPUtils.class
 
);

    private static String LOCAL_IP_STAR_STR = "192.168.";

    static {
        String ip = null;
        String hostName = null;
        try {
            hostName = InetAddress.getLocalHost().getHostName();
            InetAddress ipAddr[] = InetAddress.getAllByName(hostName);
            for (int
 
 i = 0; i < ipAddr.length; i++) {
                ip = ipAddr[i].getHostAddress();
                if (ip.startsWith(LOCAL_IP_STAR_STR)) {
                    break;
                }
            }
            if (ip == null) {
                ip = ipAddr[0].getHostAddress();
            }

        } 
 
catch (UnknownHostException e) {
            logger.error("IpHelper error.");
            e.printStackTrace();
        }

        LOCAL_IP = ip;
        HOST_NAME = hostName;

    }

    /**
     * 系統的本地IP地址
     */
    public static final String LOCAL_IP;

    /**
     * 系統的本地服務器名
     */
    public static final String HOST_NAME;

    /**
     * <p>
     * 獲取客戶端的IP地址的方法是：request.getRemoteAddr()，這種方法在大部分情況下都是有效的。
     * 但是在通過了Apache,Squid等反向代理軟件就不能獲取到客戶端的真實IP地址了，如果通過了多級反向代理的話，
     * X-Forwarded-For的值並不止一個，而是一串IP值， 究竟哪個才是真正的用戶端的真實IP呢？
     * 答案是取X-Forwarded-For中第一個非unknown的有效IP字符串。
     * 例如：X-Forwarded-For：192.168.1.110, 192.168.1.120,
     * 192.168.1.130, 192.168.1.100 用戶真實IP為： 192.168.1.110
     * </p>
     *
     * @param request
     * @return
     */
    public static String getIpAddr(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.getHeader("HTTP_CLIENT_IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_FORWARDED_FOR");
        }

        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
            if (ip.equals("127.0.0.1")) {
                /** 根據網卡取本機配置的IP */
                InetAddress inet = null;
                try {
                    inet = InetAddress.getLocalHost();
                    ip = inet.getHostAddress();
                } catch (UnknownHostException e) {
                    logger.error("IpHelper error." + e.toString());
                }
            }
        }
        /**
         * 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;
    }
}

IP工具類