JsonNode Null JsonArray Parser

Question

I am having a JsonNode response ( unirest ) which I want to parse using JSON Parser.

Now, let's say the structure is somewhat like this :

{
"expand" : "names",
"customfield_1" : null,
"customfield_2" : [ { "email":"[email protected]"},{...}]
}

So, the problem is that customfield_1 is a JsonArray and sometimes it can be null.

So, as soon as I use

JSONArray myArr = myObj.getJSONArray("customfield_1")

I get the following error:

org.json.JSONException: JSONObject["customfield_1"] is not a JSONArray.

I tried to change to JsonObject and JsonString but they also didn't help. How to avoid it ?

Matt · Accepted Answer · 2021-06-09 08:09:40Z

2

You can explicitly check if the field is null before getting the array:

JSONArray myArr = myObj.isNull("field") ? null : myObj.getJSONArray("field");

Complete example with your data:

String jsonString = "{\n" +
        "\"expand\" : \"names\",\n" +
        "\"customfield_1\" : null,\n" +
        "\"customfield_2\" : [ { \"email\":\"[email protected]\"},{ \"email\":\"[email protected]\"}]\n" +
        "}";

JSONObject myObj = new JSONObject(jsonString);
JSONArray myArr1 = myObj.isNull("customfield_1") ? null : myObj.getJSONArray("customfield_1");
JSONArray myArr2 = myObj.isNull("customfield_2") ? null : myObj.getJSONArray("customfield_2");

System.out.println(myArr1);
System.out.println(myArr2);

Output:

null
[{"email":"[email protected]"},{"email":"[email protected]"}]

answered Jun 9, 2021 at 8:09

Matt

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Comments

sanjeevRm · Accepted Answer · 2021-06-09 08:58:48Z

1

Using object mapper, you can read json and setting deserialization feature FAIL_ON_UNKNOWN_PROPERTIES as false can handle this scenario

ObjectMapper mapper = new ObjectMapper();
mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
MyObject jsonObj = mapper.readValue(jsonString, MyObject.class);

answered Jun 9, 2021 at 8:58

sanjeevRm

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