关于golang HandlerFunc。 我预计找不到404，但

Question

this is my code

  package main

  import "encoding/json"
  import "net/http"
  import "time"
  import "fmt"
  import "os"

type Profile struct {
    Name string
    Hobbies []string
}

func main() {
   http.HandleFunc("/", rootFunc)//routeSet()
   err :=http.ListenAndServe(":3000", nil)
   checkError(err)
}

func checkError(err error) {
    if err != nil {
        fmt.Println("Fatal Error", err.Error())
        os.Exit(1)
    }
}

func rootFunc(w http.ResponseWriter, r *http.Request) {
    //fmt.Println("Request url : " + r.RequestURI)
    userProfile := make(chan Profile)

    go goFun(userProfile, w, r)

    profile := <-userProfile
    js, err := json.Marshal(profile)

    if err != nil {
        http.Error(w, err.Error(), http.StatusInternalServerError)
        return
    }

    w.Header().Set("Content-Type", "application/json")
    w.Write(js)
}
func goFun(u chan Profile, w http.ResponseWriter, r *http.Request) {
//    time.Sleep(1 * time.Second)
    u <- Profile{"Alex", []string{r.RequestURI, "programming"}}
}

and I send http://localhost:3000/hello by postman

and I recieve

{
    "Name": "Alex",
    "Hobbies": [
        "/hello",
        "programming"
    ]
}

I expected 404 not found, because I use HandleFunc() only for "/"

but i received normal result.

........................... env. go 1.6 max osx

...........................

Answer 1

"/" is a rooted subtree and matches basically everything. See https://golang.org/pkg/net/http/#ServeMux . (Always consult the documentation before making any assumptions.)