go语言map字典 and struct结构体 转 bsonM

 map->bsonM

//map转bsonm
func ToBsonM(r interface{}) bson.M {
	result := make(bson.M)
	v := reflect.ValueOf(r)
	t := reflect.TypeOf(r)

	for i := 0; i < v.NumField(); i++ {
		filed := v.Field(i)
		tag := t.Field(i).Tag
		key := tag.Get("json")
		if key == "" || key == "-" || key == "_id" {
			continue
		}
		keys := strings.Split(key, ",")
		if len(keys) > 0 {
			key = keys[0]
		}
		// TODO: 处理字段嵌套问题
		switch filed.Kind() {
		case reflect.Int, reflect.Int64:
			v := filed.Int()
			if v != 0 {
				result[key] = v
			}
		case reflect.String:
			v := filed.String()
			if v != "" {
				result[key] = v
			}
		case reflect.Bool:
			result[key] = filed.Bool()
		case reflect.Ptr:

		case reflect.Float64:
			v := filed.Float()
			if v != 0 {
				result[key] = v
			}
		case reflect.Float32:
			v := filed.Float()
			if v != 0 {
				result[key] = v
			}
		default:
		}
	}
	return result
}

struct->bsonM

// ToMap 结构体转为Map[string]interface{}
func StructToMap(in interface{}, tagName string) (map[string]interface{}, error) {
	out := make(map[string]interface{})

	v := reflect.ValueOf(in)
	if v.Kind() == reflect.Ptr {
		v = v.Elem()
	}

	if v.Kind() != reflect.Struct { // 非结构体返回错误提示
		return nil, fmt.Errorf("ToMap only accepts struct or struct pointer; got %T", v)
	}

	t := v.Type()
	// 遍历结构体字段
	// 指定tagName值为map中key;字段值为map中value
	for i := 0; i < v.NumField(); i++ {
		fi := t.Field(i)
		if tagValue := fi.Tag.Get(tagName); tagValue != "" {
			out[tagValue] = v.Field(i).Interface()
		}
	}
	return out, nil
}