通过 Java 获取发起访问的客户端的IP地址

public String getIp(HttpServletRequest req) {
    // X-Forwarded-For位于HTTP协议的请求头
    String ip = req.getHeader("X-Forwarded-For");
     if (null == ip) {
         ip = request.getRemoteAddr();
     }
     if (ip.indexOf(',') > -1) {
        ip = ip.substring(0, ip.indexOf(',')).trim();
     }

     return ip;
}