how to check what return type is of object in jsonobject

Question

In my code I my a call to a service. from the returned json object I am interested in an object. this object is a json array. sometimes, depending on the provided info in the submit this json array object is empty or does not exist.

How can I check if the object in the json object is of type jsonarray before I create an object out from it?

JSONObject VODB = (JSONObject) JSONreturnObj.get("VODB");
 if (null != VODB.get("KNDV430")){
  if (VODB.getJSONArray("KNDV430") instanceof JSONArray){
   JSONArray KNDV430 = VODB.getJSONArray("KNDV430");
   customer.setCustResp((String) ((JSONObject)KNDV430.get(0)).get("responsible"));
 }
}

now I get a message in my server log:

org.json.JSONException: JSONObject["KNDV430"] is not a JSONArray.

which I want to avoid.

How should I adapt my code?

Answer 1

Replace

if (VODB.getJSONArray("KNDV430") instanceof JSONArray)

with

if (VODB.get("KNDV430") instanceof JSONArray)

Answer 2

You're getting that error from the first getJSONArray in the condition of the if. So this should work:

JSONObject VODB = (JSONObject) JSONreturnObj.get("VODB");
if (null != VODB.get("KNDV430")){
    if (VODB.get("KNDV430") instanceof JSONArray){
        JSONArray KNDV430 = VODB.getJSONArray("KNDV430");
        ...
    }
}

Answer 3

您可以查看方法JSONObject.getJSONArray（）的源代码。