解决golanghttp.FileServer遇到的坑

package main
import (
  "fmt"
  "net/http"
  "os"
  "path"
  "strings"
)
var staticfs = http.FileServer(http.Dir("D:\\code\\20160902\\src\\"))
func main() {
  //浏览器打开的时候显示的就是D:\\code\\20160902\\src\\client目录下的内容"
  http.Handle("/client/", http.FileServer(http.Dir("D:\\code\\20160902\\src\\")))
  http.HandleFunc("/static/", static)
  http.HandleFunc("/js/", js)
  http.HandleFunc("/", route)
  http.ListenAndServe(":1789", nil)
}
func route(w http.ResponseWriter, r *http.Request) {
  fmt.Println(r.URL)
  fmt.Fprintln(w, "welcome")
  r.Body.Close()
}
//这里可以自行定义安全策略
func static(w http.ResponseWriter, r *http.Request) {
  fmt.Printf("访问静态文件:%s\n", r.URL.Path)
  old := r.URL.Path
  r.URL.Path = strings.Replace(old, "/static", "/client", 1)
  staticfs.ServeHTTP(w, r)
}
//设置单文件访问,不能访问目录
func js(w http.ResponseWriter, r *http.Request) {
  fmt.Printf("不能访问目录:%s\n", r.URL.Path)
  old := r.URL.Path
  name := path.Clean("D:/code/20160902/src" + strings.Replace(old, "/js", "/client", 1))
  info, err := os.Lstat(name)
  if err == nil {
    if !info.IsDir() {
      http.ServeFile(w, r, name)
    } else {
      http.NotFound(w, r)
    }
  } else {
    http.NotFound(w, r)
  }
}