[TOC] > [參考](https://uber-go.github.io/fx/get-started/registration.html) ## 概述 有時候,初始化函數是接口函數 ``` type Route interface { http.Handler // Pattern reports the path at which this is registered. Pattern() string } func (*EchoHandler) Pattern() string { return "/echo" } func NewServeMux(route Route) *http.ServeMux { mux := http.NewServeMux() mux.Handle(route.Pattern(), route) return mux } // main fx.Provide( NewHTTPServer, NewServeMux, fx.Annotate( NewEchoHandler, fx.As(new(Route)), ), zap.NewExample, ), ```