在 Go 中解组 json

Question

I've got the following json to work with:

jsonStr := `{"Ok":[true,{"amount_awaiting_confirmation":"0","amount_awaiting_finalization":"0","amount_currently_spendable":"0","amount_immature":"0","amount_locked":"0","last_confirmed_height":"551632","minimum_confirmations":"10","total":"0"}]}`

Here's how I'm handling it now:

    resMap := make(map[string]interface{}, 0)
    json.Unmarshal([]byte(jsonStr), &resMap)
    if val, ok := resMap["Ok"]; ok {
        tup := val.([]interface{})
        wMap := tup[1].(map[string]interface{})

        amountAwaitingConfirmation, _ := strconv.ParseInt(wMap["amount_awaiting_confirmation"].(string), 10, 64)
        amountAwaitingFinalization, _ := strconv.ParseInt(wMap["amount_awaiting_finalization"].(string), 10, 64)
        amountCurrentSpendable, _ := strconv.ParseInt(wMap["amount_currently_spendable"].(string), 10, 64)
        amountImmature, _ := strconv.ParseInt(wMap["amount_immature"].(string), 10, 64)
        amountLocked, _ := strconv.ParseInt(wMap["amount_locked"].(string), 10, 64)
        lastConfirmedHeight, _ := strconv.ParseInt(wMap["last_confirmed_height"].(string), 10, 64)
        minimumConfirmations, _ := strconv.ParseInt(wMap["minimum_confirmations"].(string), 10, 64)
        total, _ := strconv.ParseInt(wMap["total"].(string), 10, 64)
    }

Is there a simpler way to handle this struct without having to resort to generic interface{} casting?

Answer 1

One thing you can do to save yourself from all the manual type asserting is to partially unmarshal the JSON using json.RawMessage . Then you can at least use a struct to unmarshal the object part of the list.

Here's an example using the JSON string you posted (and here it is running in Go Playground ):

type OkJson struct {
    Ok []json.RawMessage
}

type Details struct {
    AmountAwaitingConfirmation string `json:"amount_awaiting_confirmation"`
    AmountAwaitingFinalization string `json:"amount_awaiting_finalization"`
    AmountCurrentlySpendable   string `json:"amount_currently_spendable"`
    AmountImmature             string `json:"amount_immature"`
    AmountLocked               string `json:"amount_locked"`
    LastConfirmedHeight        string `json:"last_confirmed_height"`
    MinimumConfirmations       string `json:"minimum_confirmations"`
    Total                      string `json:"total"`
}

func main() {
    var okj OkJson
    _ = json.Unmarshal([]byte(jsonStr), &okj)

    var aBool bool
    _ = json.Unmarshal(okj.Ok[0], &aBool)
    fmt.Println(aBool)

    var details Details
    _ = json.Unmarshal(okj.Ok[1], &details)
    fmt.Println(details)
}