## 1.IO接口 ### **Reader接口** 定义 ~~~ type Reader interface { Read(p []byte) (n int, err error) } ~~~ ### demo： ~~~ func ReadFrom(reader io.Reader, num int) ([]byte, error) { p := make([]byte, num) n, err := reader.Read(p) if err != nil { panic(err) } if n > 0 { return p[:n], nil } return p, err } func main() { reader := strings.NewReader("Hello Golang") data, err := ReadFrom(reader, 12) if err != nil { panic(err) } fmt.Println(data) } ~~~ ### **Writer接口** 定义 ~~~ type Writer interface { Write(p []byte) (n int, err error) } ~~~