Go語言的“http.Handle”和“http.HandleFunc”

這是一個建立於 的文章，其中的資訊可能已經有所發展或是發生改變。

Go語言中http package包含Handle和HandleFunc兩個函數：

func Handlefunc Handle(pattern string, handler Handler)Handle registers the handler for the given pattern in the DefaultServeMux. The documentation for ServeMux explains how patterns are matched.func HandleFuncfunc HandleFunc(pattern string, handler func(ResponseWriter, *Request))HandleFunc registers the handler function for the given pattern in the DefaultServeMux. The documentation for ServeMux explains how patterns are matched.

Handle函數的handler參數是個interface：

type Handler interface {        ServeHTTP(ResponseWriter, *Request)}

而HandleFunc的handler參數就是一個原型為func(ResponseWriter, *Request)的函數。

參考下例（使用Handle）：

package mainimport (    "net/http"    "log")type httpServer struct {}func (server httpServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {    w.Write([]byte(r.URL.Path))}func main() {    var server httpServer    http.Handle("/", server)    log.Fatal(http.ListenAndServe("localhost:9000", nil))}

使用HandleFunc：

package mainimport (    "net/http"    "log")func main() {    http.HandleFunc("/", func (w http.ResponseWriter, r *http.Request){        w.Write([]byte(r.URL.Path))    })    log.Fatal(http.ListenAndServe("localhost:9000", nil))}

根據The Go Programming Language：

A handler pattern that ends with a slash matches any URL that has the pattern as a prefix. Behind the scenes, the server runs the handler for each incoming request in a separate goroutine so that it can serve multiple requests simultaneously.

因此，如果http.Handle和http.HandleFunc所指定的handle pattern是“/”，則匹配所有的pattern；而“/foo/”則會匹配所有“/foo/*”。