http://go-tour-jp.appspot.com/#58

answer_exercise_gotour_58.go

package main

import (
	"fmt"
	"net/http"
)

type String string

type Struct struct {
	Greeting string
	Punct    string
	Who      string
}

func (str String) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, str)
}

func (str Struct) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	fmt.Fprint(w, fmt.Sprintf("%s %s %s", str.Greeting, str.Punct, str.Who))
}

func main() {
	http.Handle("/string", String("I'm a frayed knot."))
	http.Handle("/struct", &Struct{"Hello", ":", "Gophers!"})
	http.ListenAndServe("localhost:4000", nil)
}