1. 运行环境

2. 问题描述？

//: package main

import (
“fmt”
“net/http”

"github.com/gorilla/mux"

)

func homeHandler(w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, “

Hello, 欢迎来到 goblog！

“)
}

func aboutHandler(w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, “此博客是用以记录编程笔记，如您有反馈或建议，请联系 “+
“<a href="mailto:summer@example.com">summer@example.com“)
}

func notFoundHandler(w http.ResponseWriter, r *http.Request) {

w.WriteHeader(http.StatusNotFound)
fmt.Fprint(w, "<h1>请求页面未找到 :(</h1><p>如有疑惑，请联系我们。</p>")

}

func articlesShowHandler(w http.ResponseWriter, r *http.Request) {
vars := mux.Vars(r)
id := vars[“id”]
fmt.Fprint(w, “文章 ID：”+id)
}

func articlesIndexHandler(w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, “访问文章列表”)
}

func articlesStoreHandler(w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, “创建新的文章”)
}

func forceHTMLMiddleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// 1. 设置标头
w.Header().Set(“Content-Type”, “text/html; charset=utf-8”)
// 2. 继续处理请求
next.ServeHTTP(w, r)
})
}

func main() {
router := mux.NewRouter()

router.HandleFunc("/", homeHandler).Methods("GET").Name("home")
router.HandleFunc("/about", aboutHandler).Methods("GET").Name("about")

router.HandleFunc("/articles/{id:[0-9]+}", articlesShowHandler).Methods("GET").Name("articles.show")
router.HandleFunc("/articles", articlesIndexHandler).Methods("GET").Name("articles.index")
router.HandleFunc("/articles", articlesStoreHandler).Methods("POST").Name("articles.store")

// 自定义 404 页面
router.NotFoundHandler = http.HandlerFunc(notFoundHandler)

// 中间件：强制内容类型为 HTML
router.Use(forceHTMLMiddleware)

// 通过命名路由获取 URL 示例
homeURL, _ := router.Get("home").URL()
fmt.Println("homeURL: ", homeURL)
articleURL, _ := router.Get("articles.show").URL("id", "1")
fmt.Println("articleURL: ", articleURL)

http.ListenAndServe(":3000", router)

}

3. 您期望得到的结果？

//: 不太理解为什么 next.ServeHTTP(w, r) 可以调用之前的函数

4. 您实际得到的结果？