服务端获得客户端ip

/**
     * 获取客户端ip地址(可以穿透代理)
     *
     * @param request
     * @return
     */
    public static String getRemoteAddr(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();
        }
        return ip;
    }
    private static final String[] HEADERS_TO_TRY = {
        "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"};

    /***
     * 获取客户端ip地址(可以穿透代理)
     * @param request
     * @return
     */
    public static String getClientIpAddress(HttpServletRequest request) {
        for (String header : HEADERS_TO_TRY) {
            String ip = request.getHeader(header);
            if (ip != null && ip.length() != 0 && !"unknown".equalsIgnoreCase(ip)) {
                return ip;
            }
        }
        return request.getRemoteAddr();
    }
    /***
     * 获取客户端ip地址(可以穿透代理)
     * @param request
     * @return
     */
    public static String getClientIpAddr(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_X_FORWARDED_FOR");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_FORWARDED");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_CLUSTER_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_FORWARDED_FOR");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_FORWARDED");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_VIA");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("REMOTE_ADDR");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        return ip;
    }
    public static String getIpAddr(HttpServletRequest request) {
        String ip = request.getHeader("X-Real-IP");
        if (null != ip && !"".equals(ip.trim())
                && !"unknown".equalsIgnoreCase(ip)) {
            return ip;
        }
        ip = request.getHeader("X-Forwarded-For");
        if (null != ip && !"".equals(ip.trim())
                && !"unknown".equalsIgnoreCase(ip)) {
            // get first ip from proxy ip
            int index = ip.indexOf(',');
            if (index != -1) {
                return ip.substring(0, index);
            } else {
                return ip;
            }
        }
        return request.getRemoteAddr();
    }