http：紧急服务[:: 1]：57685：分配给零图中的条目

I am trying to make a vcard using golang.My code is:

    var (
    // card is a map of strings to []*vcard.Field objects
    card vcard.Card

    // destination where the vcard will be encoded to
    enc = vcard.NewEncoder(destFile) 
)
var str []string


for i, entry := range k {


    if i!=2{
        str=append(str,k[i])


        card.SetValue(vcard.FieldFormattedName, strings.Join(str[:i],""))//panic occurs here
        fmt.Println(str)

    }else if i==2{
        card.SetValue(vcard.FieldTelephone, entry)
    }else{
        card.SetValue(vcard.FieldOrganization, entry)
    }




    // set the value of a field and other parameters by using card.Set
    card.Set(vcard.FieldName, &vcard.Field{
        Value: strings.Join(str[:2], ";"),
        Params: map[string][]string{
            vcard.ParamSortAs: []string{
                k[0] + " " + k[1],
            },
        },
    })

The json document which has to be stored in vcf is:

      {"firstname":"Vilas","lastname":"Prakash","mobile":"8732647482","organisation":"Dbjb"}

I have marshalled the json to []string.On executing I am getting the following error:

    http: panic serving [::1]:57685: assignment to entry in nil map

Can anyone help me???Or Is there any other way of creating .vcf or vcard in golang using json document as input???

You haven't initialized your map. I suggest you read up on how maps work in Go https://blog.golang.org/go-maps-in-action

In the meantime

var card vcard.Card

should be

var card = make(vcard.Card)

I'm not familiar with the vcard data structure. But you mention that it should be a map -> string][]*vcard.Field.. If the above make fails change it to

var card = make(map[string][]*vcard.Field)