显示带有标准http包的自定义404错误页面

我通常这样做：

package mainimport (    "fmt"    "net/http")func main() {    http.HandleFunc("/", homeHandler)    http.HandleFunc("/smth/", smthHandler)    http.ListenAndServe(":12345", nil)}func homeHandler(w http.ResponseWriter, r *http.Request) {    if r.URL.Path != "/" {        errorHandler(w, r, http.StatusNotFound)        return    }    fmt.Fprint(w, "welcome home")}func smthHandler(w http.ResponseWriter, r *http.Request) {    if r.URL.Path != "/smth/" {        errorHandler(w, r, http.StatusNotFound)        return    }    fmt.Fprint(w, "welcome smth")}func errorHandler(w http.ResponseWriter, r *http.Request, status int) {    w.WriteHeader(status)    if status == http.StatusNotFound {        fmt.Fprint(w, "custom 404")    }}

在这里，我将代码简化为仅显示自定义404，但实际上使用此设置可以做更多的事情：我使用来处理所有HTTP错误

errorHandler