golang使用http上傳下載文件

package main

import(
	"fmt"
	"io"
	"log"
	"net/http"
	"os"
	"strings"
)

func get(w http.ResponseWriter,r *http.Request){
	fmt.Println("dwadw")
	f,err:=os.Open(os.Getenv("STORAGE_ROOT")+"/objects/"+strings.Split(r.URL.EscapedPath(),"/")[2])
	if err!=nil{
		log.Println(err)
		w.WriteHeader(http.StatusNotFound)
		return
	}
	defer f.Close()
	io.Copy(w,f)
}
func main(){
	http.HandleFunc("/file",get)
	err:=http.ListenAndServe(":8080",nil)
	if err!=nil{
		fmt.Println(err)
	}
}