Go语言基础语法之四——Http请求的处理

package main

import (
   "errors"
   "net/http"
   "strings"
)

type Handler1 struct {
}
type Handler2 struct {
}
type Handler3 struct {
}

func (h * Handler1) ServeHTTP(w http.ResponseWriter, r * http.Request) {
   msg := "欢迎访问此网站1"
   w.Write([]byte(msg))
}

func (h * Handler2) ServeHTTP(w http.ResponseWriter, r * http.Request) {
   msg := "欢迎访问此网站2"
   w.Write([]byte(msg))
}

func (h * Handler3) ServeHTTP(w http.ResponseWriter, r * http.Request) {
   msg := "欢迎访问此网站3"
   w.Write([]byte(msg))
}

type HandlerRoot struct {
   http.ServeMux
   // 存放所有handler的map
   hm map[string]http.Handler
}

func (h * HandlerRoot) MapHandler(path string, handler http.Handler) error {
   if path == "" {
      return errors.New("url不能为空")
   }
   if !strings.HasPrefix(path, "/") {
      path =  "/" + path
   }
   // 去重
   if _, isExist := h.hm[path];isExist {
      return errors.New("此url已经存在")
   }
   if h.hm == nil {
      h.hm = make(map[string]http.Handler)
   }
   h.hm[path] = handler
   return nil
}

func a(w http.ResponseWriter, r *http.Request)  {
   msg := "欢迎访问此网站1"
   w.Write([]byte(msg))
}

func b(w http.ResponseWriter, r *http.Request)  {
   msg := "欢迎访问此网站2"
   w.Write([]byte(msg))
}

func c(w http.ResponseWriter, r *http.Request)  {
   msg := "欢迎访问此网站3"
   w.Write([]byte(msg))
}

func main() {
   http.HandleFunc("/", a)
   http.HandleFunc("/b", b)
   http.HandleFunc("/c", c)
   http.ListenAndServe("localhost:8080", nil)
}