【获取IP】多层代理后，出现获取是IP列表，导致一些支付平台的ip错误、或者Sign错误

1、使用下面的代码获取实际IP的时候 会出现 IP清单【49.77.233.222, 140.205.253.100】

 /**
     * 获取ip地址,防止集群、代理
     * 
     * @param request
     * @return ip
     */
    public static String getAddr(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();
        }
       
    }

2、其实这个由于多层代理所致，第一个是用户的对外公网IP，第二个是某一层的代理IP，比如阿里云的CDN 的CNAME服务器，或者独立的Apache Nginx代理服务器

3、只返回用户的正式IP，获取第一个

/**
     * 获取ip地址,防止集群、代理
     * 
     * @param request
     * @return ip
     */
    public static String getAddr(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();
        }
        // 解决出现多层代理，返回第一个作为实际IP地址
        if (MoShopUtil.isNotEmpty(ip))
        {
            String[] ips = ip.split(",");
            if (ips.length > 0)
            {
                return ips[0].trim();
            }
        }
        return ip;
    }