Golang json自定义序列化反序列化教程

type Marshaler interface {
    MarshalJSON() ([]byte, error)
}

type Unmarshaler interface {
    UnmarshalJSON([]byte) error
}

type CustomDate struct {
    time.Time
}

func (cd CustomDate) MarshalJSON() ([]byte, error) {
    return []byte(fmt.Sprintf(`"%s"`, cd.Time.Format("2006-01-02"))), nil
}

func (cd *CustomDate) UnmarshalJSON(data []byte) error {
    // 去掉引号
    s := strings.Trim(string(data), `"`)
    t, err := time.Parse("2006-01-02", s)
    if err != nil {
        return err
    }
    cd.Time = t
    return nil
}

date := CustomDate{Time: time.Now()}
jsonBytes, _ := json.Marshal(date)
fmt.Println(string(jsonBytes)) // 输出："2025-04-05"

type User struct {
    ID    int    `json:"id"`
    Name  string `json:"name"`
    Email string `json:"email,omitempty"`
    Admin bool   `json:"-"`
}

func (cd *CustomDate) MarshalJSON() ([]byte, error) {
    if cd == nil {
        return []byte("null"), nil
    }
    return []byte(fmt.Sprintf(`"%s"`, cd.Time.Format("2006-01-02"))), nil
}

type Message struct {
    Type      string          `json:"type"`
    Payload   json.RawMessage `json:"payload"`
}