fmt

Package fmt implements formatted I/O with functions analogous to C’s printf and scanf.

The format ‘verbs’ are drived from C’s but are simpler.

fmt.Println

Println formats using the default formats for its operands and writes to standard output.

Spaces are always added between operands and a newline is appended.

net/http

Package http provides HTTP client and server implementations.

Get, Head, Post, and PostForm make HTTP (or HTTPs) requests:

resp, err := http.Get("http://example.com")
resp, err := http.Post("http://example.com/upload", "image/jpeg", &buf)
resp, err := http.PostForm("http://example.com/form", url.Values{"key":{"Value"}, "id":{"123"}})

The client must close the response body when finished with it:

resp, err := http.Get("http://example.com/")
if err != nil {
    // handle error
}
defer resp.Body.Close()
body, err := ioutil.ReadAll

《理解:=||nil||defer in Go》