使用go，如何将map [int] T转换为map [string] T以与JSON一起使用？

Question

My code is getting plastered with functions like the following:

func TransformMapClassA(mapOfIntToClassA map[int]*ClassA) map[string]*ClassA {
  mapOfStringToClassA := make(map[string]*ClassA)
  for id, obj := range mapOfIntToClassA {
    mapOfStringToClassA[fmt.Sprintf("%d" obj.Id)] = obj
  }
  return mapOfStringToClassA
}

written once for each class in my application. I'm doing this, so I can json.Marshal the existing map. Is there a generic way of doing this, so I don't have to write one function per class? I've tried doing things like:

type Int64JSON int64 `json:",string"`

and using Int64JSON in my original maps, but the compiler doesn't like the json tag in a type definition :(

Many thanks in advance!

Answer 1

If you still want to use reflection to create a function that returns a map[string]interface{} from any type of map, you can do the following:

func TransformMap(m interface{}) (map[string]interface{}, error) {

    v := reflect.ValueOf(m)

    if v.Kind() != reflect.Map {
        return nil, errors.New("Map required")
    }

    result := make(map[string]interface{}, v.Len())

    keys := v.MapKeys()
    for _, k := range keys {
        result[fmt.Sprint(k.Interface())] = v.MapIndex(k).Interface()
    }

    return result, nil
}

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