获取nginx代理情况下的真实ip

location  /xxx/ {
    proxy_pass http://192.168.4.5:8080/xxx/;
    proxy_set_header  Host             $host;
    proxy_set_header  X-Real-IP        $remote_addr;
    proxy_set_header  X-Forwarded-For  $proxy_add_x_forwarded_for;
}

public String getRemoteIp(HttpServletRequest request) {
    String ip = request.getHeader("x-forwarded-for");
    logger.info("===========x-forwarded-for======="+ip);//这一步一般能获取到
    if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
        ip = request.getHeader("Proxy-Client-IP");
        logger.info("===========Proxy-Client-IP======="+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();
    }
    final String[] arr = ip.split(",");for (final String str : arr) {
        if (!"unknown".equalsIgnoreCase(str)) {
            ip = str;
            break;
        }
    }
    return ip;
}