java 获取用户的ip都是 127.0.0.1

通过nginx反向代理，java获取ip地址时，总是127.0.0.1。是因为nginx请求的时候没有带有
request信息，设置nginx转发的时候，带上request的信息就可以了。

java代码：

    /**
     * 先从反向代理里找IP
     *
     * @param request
     * @return
     */
    public static String getIp(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");
        if (ip != null && ip.length() != 0 && !"unknown".equalsIgnoreCase(ip)) {
            // 多次反向代理后会有多个ip值，第一个ip才是真实ip
            if (ip.indexOf(",") != -1) {
                ip = ip.split(",")[0];
            }
        }
        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.getHeader("HTTP_CLIENT_IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("HTTP_X_FORWARDED_FOR");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("X-Real-IP");
        }
        if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        if ("127.0.0.1".equals(ip) || "0:0:0:0:0:0:0:1".equals(ip)) {
            try {
                ip = InetAddress.getLocalHost().getHostAddress();
            } catch (Exception e) {
                ip = "";
            }
        }
        System.out.println("获取客户端ip: " + ip);
        return ip;
    }

nginx配置：

location / {
    proxy_set_header x-forwarded-for  $remote_addr;
}