无Nginx代理场景
业务层通过获取请求头参数即可拿到客户端IP
request.getRemoteAddr();复制代码
一级Nginx代理
使用代理后直接读取请求头参数会读取到代理服务器的IP地址，而非真实客户端IP
解决方法是添加Nginx请求头参数提前保存客户端IP
nginx.conf配置加入内容
location / { ... # IP地址转发 proxy_set_header X-Real-IP $remote_addr; proxy_set_header X-Real-Port $remote_port; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; }复制代码 业务层读取nginx配置的请求头参数即可
public static String getIpAddr(HttpServletRequest request) { String ip = request.getHeader("X-Real-IP"); if (ip == null || ip.length() == 0 || " unknown ".equalsIgnoreCase(ip)) { ip = request.getHeader("Proxy-Client-IP"); log.info("【Proxy-Client-IP】 {}", ip); } if (ip == null || ip.length() == 0 || " unknown ".equalsIgnoreCase(ip)) { ip = request.getHeader("WL-Proxy-Client-IP"); log.info("【WL-Proxy-Client-IP】{}", ip); } if (ip == null || ip.length() == 0 || " unknown ".equalsIgnoreCase(ip)) { ip = request.getHeader("X-Forwarded-For"); log.info("【X-Forwarded-For】{}", ip); } if (ip == null || ip.length() == 0 || " unknown ".equalsIgnoreCase(ip)) { ip = request.getRemoteAddr(); log.info("【unknown】{}", ip); } return ip; }复制代码 多级Nginx代理
若存在多级Nginx代理，则需要在第一级代理时获取客户端IP，在后续代理逐层传递
第一级代理配置同上，第N级代理配置nginx.conf如下
location /{ # IP地址转发 proxy_set_header X-Real-IP $X-Real-IP; proxy_set_header X-Real-Port $X-Real-Port; proxy_set_header X-Forwarded-For $X-Forwarded-For;}复制代码 业务层保持不变即可读取到传递的IP地址
阿里云CDN转发
在已经存在nginx代理的场景下，加入CDN后源客户端IP在CDN处被转发，故第一级nginx代理使用$remote_addr参数读取到的是CDN服务的地址，而根据一般约定，CDN转发会将IP地址存放在X-Forwarded-For参数下
修改顶级Nginx配置以支持优先获取CDN代理地址，也可以通过修改业务层读取优先级实现
location / { ... # IP地址转发 # proxy_set_header X-Real-IP $remote_addr; # proxy_set_header X-Real-Port $remote_port; proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for; }复制代码 但经过对阿里云CDN测试，发现X-Forwarded-For下不仅包含真实客户端IP也包含CDN服务IP，故业务层需要做一定的处理进行区分
如图，第一个为真实客户端IP，第二个为CDN代理IP
public static String getIpAddr(HttpServletRequest request) { String ip = request.getHeader("X-Real-IP"); if (ip == null || ip.length() == 0 || " unknown ".equalsIgnoreCase(ip)) { ip = request.getHeader("Proxy-Client-IP"); log.info("【Proxy-Client-IP】 {}", ip); } if (ip == null || ip.length() == 0 || " unknown ".equalsIgnoreCase(ip)) { ip = request.getHeader("WL-Proxy-Client-IP"); log.info("【WL-Proxy-Client-IP】{}", ip); } if (ip == null || ip.length() == 0 || " unknown ".equalsIgnoreCase(ip)) { ip = request.getHeader("X-Forwarded-For"); if (ip.contains(",")) { // 通过阿里云CDN转发后可能读取到2个IP地址 String[] cdnMutilIp = ip.split(","); ip = cdnMutilIp[0]; } log.info("【X-Forwarded-For】{}", ip); } if (ip == null || ip.length() == 0 || " unknown ".equalsIgnoreCase(ip)) { ip = request.getRemoteAddr(); log.info("【unknown】{}", ip); } return ip; }}复制代码