java代码，如何获取请求中 网络协议、IP、端口号、项目根路径

pubulic static String getRequestPrefix(HttpServletRequest request){

           //获取网络协议

            String networkProtocol = request.getScheme();

            //网络IP

            String ip = request.getServerName();

            //端口号

            int port = request.getServerPort();

            //项目发布路径

            String webApp = request.getContextPath();

            String urlPrefix = networkProtocol+"://"+ip+":"+port+webApp;

            return urlPrefix;

}