Go的依赖倒置原则：代码运行依赖内部的抽象接口
package main
import "fmt"
type Note interface {
GetType() string
}
type Lineation struct {
}
func (line Lineation) GetType() string {
return "划线笔记"
}
// NoteObj 声明为接口类型，便于后续扩展
type Reader struct {
NoteObj Note
}
func (read Reader) Read(){
fmt.Println("正在学习：", read.NoteObj.GetType())
}
func main () {
note := Lineation{}
reader := Reader {
NoteObj:note,
}
reader.Read()
}