package mainimport "fmt"import "net/http"func home(w http.ResponseWriter, r *http.Request) {  fmt.Fprintf(w, "What!")}func bar(w http.ResponseWriter, r *http.Request) {  fmt.Fprintf(w, "Bar!")}func main() {  http.HandleFunc("/", home)  http.HandleFunc("/foo", bar)  http.ListenAndServe(":5678", nil)}如果我訪問/foo，bar將運(yùn)行。如果我訪問/或/any/other/path，home將運(yùn)行。知道為什么會(huì)這樣嗎？我該如何處理 404？