java实现判断ip是否在指定ip区间的工具类

思路：
利用ip和ip区间两端的值调用ipIsValid方法。
（视频教程推荐：java课程）
工具类：
import org.apache.commons.lang.StringUtils;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;

import javax.servlet.http.HttpServletRequest;


public class IPUtil {

	/**
     * 获得当前ip
     * @return
     */
    public static String getIP(){
        ServletRequestAttributes servletRequestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        if(servletRequestAttributes == null) {
            return "127.0.0.1";
        }

        HttpServletRequest request = servletRequestAttributes.getRequest();
        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 ("0:0:0:0:0:0:0:1".equals(ip)) {
            ip = "127.0.0.1";
        }
        return ip;
    }

    /**
     * 判断IP是否在指定范围
     * @param ipStart
     * @param ipEnd
     * @param ip
     * @return
     */
    public static boolean ipIsValid(String ipStart,String ipEnd, String ip) {
        if (StringUtils.isEmpty(ipStart)) {
            throw new NullPointerException("起始IP不能为空！");
        }
        if (StringUtils.isEmpty(ipEnd)) {
            throw new NullPointerException("结束IP不能为空！");
        }
        if (StringUtils.isEmpty(ip)) {
            throw new NullPointerException("IP不能为空！");
        }
        ipStart = ipStart.trim();
        ipEnd = ipEnd.trim();
        ip = ip.trim();
        final String REGX_IP = "((25[0-5]|2[0-4]\\d|1\\d{2}|[1-9]\\d|\\d)\\.){3}(25[0-5]|2[0-4]\\d|1\\d{2}|[1-9]\\d|\\d)";
        final String REGX_IPB = REGX_IP + "\\-" + REGX_IP;
        if (!ipStart.matches(REGX_IP) || !ip.matches(REGX_IP) || !ipEnd.matches(REGX_IP)) {
            return false;
        }
        String[] sips = ipStart.split("\\.");
        String[] sipe = ipEnd.split("\\.");
        String[] sipt = ip.split("\\.");
        long ips = 0L, ipe = 0L, ipt = 0L;
        for (int i = 0; i < 4; ++i) {
            ips = ips << 8 | Integer.parseInt(sips[i]);
            ipe = ipe << 8 | Integer.parseInt(sipe[i]);
            ipt = ipt << 8 | Integer.parseInt(sipt[i]);
        }
        if (ips > ipe) {
            long t = ips;
            ips = ipe;
            ipe = t;
        }
        return ips <= ipt && ipt <= ipe;
    }


}