Go http.ListenAndServe 报错

package main

import (
   "io/ioutil"
   "net/http"
   "os"
)

func main() {
   http.HandleFunc("/list/", func(writer http.ResponseWriter, request *http.Request) {
      path := request.URL.Path[len("/list/"):]
      file, err := os.Open(path)
      if err != nil {
         panic(err)
      }
      defer file.Close()

      all, err := ioutil.ReadAll(file)
      if err != nil {
         panic(err)
      }
      writer.Write(all)

   })
   err := http.ListenAndServe("0.0.0.0:8000 ", nil)
   if err != nil {
      panic(err)
   }
}

panic: listen tcp: lookup tcp/8000 : nodename nor servname provided, or not known goroutine 1 [running]: main.main() /Users/doufangyu/GolandProjects/Go-Learngo/errhandling/filelistenserver/web.go:29 +0x7f

求大佬给个解决思路