Decoding JSON int into string

Question

I have this simple JSON string where I want user_id to be converted into string when doing json.Unmarshal:

{"user_id": 344, "user_name": "shiki"} 

I have tried this:

type User struct {   Id       string `json:"user_id,int"`   Username string `json:"user_name"` }  func main() {   input := `{"user_id": 344, "user_name": "shiki"}`   user := User{}   err := json.Unmarshal([]byte(input), &user)   if err != nil {     panic(err)   }    fmt.Println(user) } 

But I just get this error:

panic: json: cannot unmarshal number into Go value of type string 

Playground link: http://play.golang.org/p/mAhKYiPDt0

Answer 1

You can use the type json.Number which is implemented as a string:

type User struct {         Id       json.Number `json:"user_id"`         Username string      `json:"user_name"` } 

Then you can simply convert it in any other code:

stringNumber := string(userInstance.Id) 

Playground: https://play.golang.org/p/2BTtWKkt8ai