1.正常的逻辑，如果我们直接请求服务，那么在request.getRemoteAddress()就可以拿到原始客户端请求的ip

2.如果新增了nginx代理,那么就只能借助XFF从header里面取了

private String getIpAddr(HttpServletRequest servletRequest) {

        String ips = servletRequest.getHeader("x-forwarded-for");
        if (ips == null || ips.length() == 0 || "unknown".equalsIgnoreCase(ips)) {
            ips = servletRequest.getHeader("Proxy-Client-IP");
        }
        if (ips == null || ips.length() == 0 || "unknown".equalsIgnoreCase(ips)) {
            ips = servletRequest.getHeader("WL-Proxy-Client-IP");
        }
        if (ips == null || ips.length() == 0 || "unknown".equalsIgnoreCase(ips)) {
            ips = servletRequest.getRemoteAddr();
        }

        String[] ipArray = ips.split(",");
        String clientIP = "";
        for (String ip : ipArray) {
            if (!("unknown".equalsIgnoreCase(ip))) {
                clientIP = ip;
                break;
            }
        }
        return clientIP;
    }

3.如果全部署在k8s，会过一道网络代理，那么在网络代理这会做一次NAT，所以如果不想丢失源ip就只能修改externalTrafficPolicy=local 不进行路由，直接在当前节点处理