Golang 反射解析 JSON 与结构体映射技巧

type User struct {
    Name string `json:"name"`
    Age  int    `json:"age"`
    Email string `json:"email,omitempty"`
}

func MapJSONToStruct(data map[string]interface{}, obj interface{}) {
    v := reflect.ValueOf(obj).Elem()
    t := v.Type()

    for i := 0; i < v.NumField(); i++ {
        field := v.Field(i)
        fieldType := t.Field(i)
        tag := fieldType.Tag.Get("json")
        if tag == "" || tag == "-" {
            continue
        }
        // 去掉可能的 ,omitempty
        jsonKey := strings.Split(tag, ",")[0]

        if val, exists := data[jsonKey]; exists {
            switch field.Kind() {
            case reflect.String:
                if str, ok := val.(string); ok {
                    field.SetString(str)
                }
            case reflect.Int:
                if num, ok := val.(float64); ok {
                    field.SetInt(int64(num))
                }
            // 可继续扩展其他类型
            }
        }
    }
}

func inspectValue(v interface{}) {
    rv := reflect.ValueOf(v)
    rt := reflect.TypeOf(v)

    fmt.Printf("Type: %s, Kind: %s\n", rt.Name(), rt.Kind())
    
    switch rv.Kind() {
    case reflect.Map:
        for _, key := range rv.MapKeys() {
            value := rv.MapIndex(key)
            fmt.Printf("Key: %v, Value: %v\n", key.Interface(), value.Interface())
        }
    case reflect.Slice:
        for i := 0; i < rv.Len(); i++ {
            fmt.Printf("Item[%d]: %v\n", i, rv.Index(i).Interface())
        }
    // 其他类型处理...
    }
}