nginx做反向负载均衡，后端服务器获取真实客户端ip

nginx做反向负载均衡，后端服务器获取真实客户端ip

首先，在前端nginx上需要做如下配置：

location /

proxy_set_hearder host                $host;

proxy_set_header X-forwarded-for $proxy_add_x_forwarded_for;

proxy_set_header X-real-ip           $remote_addr;

};

nginx会在把请求转向后台real-server前把http报头中的ip地址进行替换；这样操作完成后，real-server也需要做一些操作；

 可是，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，此时取第一个Ip地址就可以了，相关代码如下:

public String getClientIp(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();

        }
        if(ip.trim().contains(",")){//为什么会有这一步，因为经过多层代理后会有多个代理，取第一个ip地址就可以了
            String [] ips=ip.split(",");
            ip=ips[0];
        }
        return ip;
    }