使用AWS-GO-SDK的UnmarshalMap

Question

// UserInfo 用来解构返回的数据
type UserInfo struct {
    gender     string            `dynamo:"gender"`
    product    string            `dynamo:"product"`
    id         string            `dynamo:"id"`
    createTime int               `dynamo:"create_time"`
    name       string            `dynamo:"name"`
}

// GetUserInfoByID 根据userId在supe_user表取回用户信息
func GetUserInfoByID(userId string) (UserInfo, error) {
    queryInput := dynamodb.GetItemInput{
        Key: map[string]*dynamodb.AttributeValue{
            "userId": {
                S: aws.String(userId),
            },
        },
        TableName: aws.String("user"),
    }
    result, err := dbsession.DynamoDB.GetItem(&queryInput)
    userInfo := UserInfo{}
    if err != nil {
        fmt.Println(err.Error())
        return userInfo, err
    }
    unmarshalMapErr := dynamodbattribute.UnmarshalMap(result.Item, &userInfo)
    if unmarshalMapErr != nil {
        return userInfo, err
    }
    fmt.Println(result.Item)
    fmt.Println(userInfo.name)
    return userInfo, nil
}

Why is this not working? It did not throw any error, just not working... My guess is something wrong with my UserInfo type, but can't figure the right way to do this, help, please.

Answer 1

In Go, a name is exported if it begins with a capital letter. You should make first letters of fields UPPERCASED to make sure they're exported, like:

type UserInfo struct {
    Gender     string            `dynamo:"gender"`
    Product    string            `dynamo:"product"`
    Id         string            `dynamo:"id"`
    CreateTime int               `dynamo:"create_time"`
    Name       string            `dynamo:"name"`
}

more info: https://www.goinggo.net/2014/03/exportedunexported-identifiers-in-go.html