Go-在json.marshal中自动将字符串值转换为int值

Question

I have []map[string]string.Values present can be integer(in string form) "1".I want to automatically convert to int value like 1.

Example:

map1 := []map[string]string{
    {"k1": "1", "k2": "some value"},
    {"k1": "-12", "k2": "some value"},
}

I want to convert it to json like this using json.marshal

 {{"k1":1,"k2":"some value"}{"k1":-12,"k1":"some value"}}

How do I achive this.

Answer 1

You can create a custom type, and implement the json.Marshaller interface on that type. That method implementation can transparently do the string -> int conversion:

type IntValueMarshal []map[string]string

func (ivms IntValueMarshal) MarshalJSON() ([]byte, error) {
    // create a new map to hold the converted elements
    mapSlice := make([]map[string]interface{}, len(ivms))

    // range each of the maps
    for i, m := range  ivms {
        intVals := make(map[string]interface{})

        // attempt to convert each to an int, if not, just use value
        for k, v := range m {
            iv, err := strconv.Atoi(v)
            if err != nil {
                intVals[k] = v
                continue
            }
            intVals[k] = iv
        }

        mapSlice[i] = intVals
    }
    // marshal using standard marshaller
    return json.Marshal(mapSlice)
}

To use it, something like:

values := []map[string]string{
    {"k1": "1", "k2": "somevalue"},
}

json.Marshal(IntValueMarshal(values))