func LoadFile(w http.ResponseWriter, r *http.Request, p httprouter.Params) {
url:= p.ByName("url")
file, err:= os.Open("./" + url)
if err!= nil {
httputil.WriteErrorResponse(w, "文件不存在")
return
}
defer file.Close()
buff, _ := ioutil.ReadAll(file)
w.Write(buff)
}
原文：https://www.cnblogs.com/lemonzwt/p/11925081.html