create JSONArray from JSONObject

Question

Good day all

I am having trouble parsing a JSONArray from a JSONObject. I might just be misunderstanding.

Creating the JSONObject to send:

int i = 0;
JSONArray jsonArray = new JSONArray();
String line;

while ((line = bufferedReader.readLine()) != null) {
    JSONObject rule = new JSONObject().put("rule", line);
    jsonArray.put(i,rule);
    i++;
}
return (new JSONObject().put(jsonStrings.REQUEST_RULES_ALL_RESPONSE, jsonArray));

This send a json array within a json object, to make things simpler. This is correct.

the returned object is in this format:

{"REQUEST_RULES_ALL_RESPONSE":[ 
        {"rule":"something"},
        {"rule":"something"},
        {"rule":"something"}  ]}

I would like to parse this into a List RULES. Reading the JSONObject recieved:

//this returns the object as described above
JSONObject jsonObject = serverData.SendData(new JSONObject().put(jsonStrings.REQUEST_RULES_ALL, " ")); 

//Trying to Convert to JSONArray, the get strings are correct, 
//notice the REQUEST and REQUEST RESPONSE.

//problem line below
JSONArray JSONFirewallRules = new JSONArray ((JSONArray)jsonObject.get(jsonStrings.REQUEST_RULES_ALL_RESPONSE));

ERROR: org.json.JSONException: Not a primitive array: class org.json.JSONArray

I do not understand why this is a problem. I would like to get the JSONArray from the object.

jsonArray.put(i,rule); to jsonArray.put(rule);

Sumanth Jois
– Sumanth Jois

2016-03-29 08:34:52 +00:00
Commented Mar 29, 2016 at 8:34 — Sumanth Jois
– Sumanth Jois, Commented Mar 29, 2016 at 8:34

Sakamiai · Accepted Answer · 2016-03-29 08:56:47Z

3

In the problematic line, instead of casting to a JSONArray, use getJSONArray:

JSONArray JSONFirewallRules = jsonObject.getJSONArray(jsonStrings.REQUEST_RULES_ALL_RESPONSE);

However the exception isn't a cast exception, but a constructor exception where you are trying to build a JSONArray object from an unsupported list of items, which is another JSONArray :)

answered Mar 29, 2016 at 8:56

Sakamiai

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Comments

Qamar · Accepted Answer · 2016-03-31 10:48:20Z

1

jsonObject.getJSONArray(key) throw exception in case key not found
Use jsonObject.opt... methods. These methods just return null if key not found in json object
Use jsonObject.optJSONArray(key) instead of jsonObject.getJSONArray(key)

answered Mar 31, 2016 at 10:48

Qamar

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