Golang如何构建简易的笔记应用

type Note struct {    Title     string    `json:"title"`    Content   string    `json:"content"`    CreatedAt time.Time `json:"created_at"`}

func saveNotes(notes []Note) error {    data, err := json.MarshalIndent(notes, "", "  ")    if err != nil {        return err    }    return ioutil.WriteFile("notes.json", data, 0644)}

func loadNotes() ([]Note, error) {    var notes []Note    data, err := ioutil.ReadFile("notes.json")    if err != nil {        return notes, nil // 文件不存在时返回空列表    }    json.Unmarshal(data, &notes)    return notes, nil}

func addNote(title, content string) error {    notes, err := loadNotes()    if err != nil {        return err    }    newNote := Note{        Title:     title,        Content:   content,        CreatedAt: time.Now(),    }    notes = append(notes, newNote)    return saveNotes(notes)}

func main() {    args := os.Args[1:]    if len(args) < 1 {        fmt.Println("Usage: note add|list|find [args...]")        return    }
switch args[0] {case "add":    if len(args) != 3 {        fmt.Println("Usage: note add