根目录URL处理

package main

import (
    "net/http"
)

func main() {
    http.Handle("/", http.FileServer(http.Dir("/tmp"))
    log.Fatal(http.ListenAndServe(":8080", nil))

    // or
    // log.Fatal(http.ListenAndServe(":8080", 
    //          http.FileServer(http.Dir("/usr/share/doc"))))
}

备注：如果使用暴露dir的方式存在安全隐患的，也可以采用serveFile的方式进行

http.HandleFunc("/static2/", func(w http.ResponseWriter, r *http.Request) {
    // !TODO Add check file access or other thing
    http.ServeFile(w, r, r.URL.Path[1:])
})

前缀目录url处理

package main

import (
    "net/http"
)

func main() {
    http.Handle("/tmp/", http.StripPrefix("/tmp/", http.FileServer(http.Dir("/tmp/static"))))
    http.ListenAndServe(":8080", nil)
}

参考：

1. Golang. What to use? http.ServeFile(..) or http.FileServer(..)?
2. golang Http ServerFile
3. golang Http FileServer