IP工具类

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

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

/**
 * 获取IP工具类
 * @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;

    }

    /**
     * 系统的本地IP地址
     */
    public static final String LOCAL_IP;

    /**
     * 系统的本地服务器名
     */
    public static final String HOST_NAME;

    /**
     * <p>
     * 获取客户端的IP地址的方法是：request.getRemoteAddr()，这种方法在大部分情况下都是有效的。
     * 但是在通过了Apache,Squid等反向代理软件就不能获取到客户端的真实IP地址了，如果通过了多级反向代理的话，
     * X-Forwarded-For的值并不止一个，而是一串IP值， 究竟哪个才是真正的用户端的真实IP呢？
     * 答案是取X-Forwarded-For中第一个非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 用户真实IP为： 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")) {
                /** 根据网卡取本机配置的IP */
                InetAddress inet = null;
                try {
                    inet = InetAddress.getLocalHost();
                    ip = inet.getHostAddress();
                } catch (UnknownHostException e) {
                    logger.error("IpHelper error." + e.toString());
                }
            }
        }
        /**
         * 对于通过多个代理的情况， 第一个IP为客户端真实IP,多个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;
    }
}