Java: Looping through nested JSON Object

Question

I have the following structure for storing messages:

{
    "Channel_12": [
        ["[{\"to\":\"Bill\",\"msg\":\"Hello\",\"time\":\"10:36\"}]"], "[{\"agentName\":\"demo\",\"msg\":\"Hello 2\",\"time\":\"10:37\"}]"
    ],
    "Channel_34": [
        ["[{\"to\":\"Bill\",\"msg\":\"Hey 1\",\"time\":\"10:37\"}]"], "[{\"agentName\":\"demo\",\"msg\":\"Hey 2\",\"time\":\"10:38\"}]"
    ] }

I'm now trying to loop through and get each message for a given channel, lets say i want to fetch all the messages for channel Channel_12.

Currently i have the following code:

        org.codehaus.jettison.json.JSONArray c = obj.getJSONArray("Channel_12");

        for (int i = 0 ; i < c.length(); i++) {
            JSONObject obj = c.getJSONObject(i); <!-- Exception is here

            System.out.println(obj.getString("to").toString());
            System.out.println(obj.getString("msg").toString());

        }

But am getting the following exception:

org.codehaus.jettison.json.JSONException: JSONArray[0] is not a JSONObject.
    at org.codehaus.jettison.json.JSONArray.getJSONObject(JSONArray.java:277)
    at im.Client$HistoryJSON.getHistory(Client.java:7229)
    at im.Client$32$4.run(Client.java:2246)
    at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:715)
    at java.awt.EventQueue.access$400(EventQueue.java:82)
    at java.awt.EventQueue$2.run(EventQueue.java:676)
    at java.awt.EventQueue$2.run(EventQueue.java:674)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:86)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:685)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:296)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:196)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:188)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

Any ideas?

Why are you storing escaped JSON within JSON? That makes little sense. If you store it without escaping it, then your code would work i.e. { "Channel_12":[{"to":"Bill"... etc — Charles Goodwin
– Charles Goodwin, Commented Dec 3, 2013 at 11:23

Jaydipsinh Zala · Accepted Answer · 2013-12-03 11:18:52Z

1

Chage your code like,

        JSONArray c = jsonObject.getJSONArray("Channel_12");  //Change your code from here
        JSONArray array = c.getJSONArray(0);
        String data = c.getString(1);
        Log.i("#Values", array.getString(0) + "\t" + data);

See my result,

enter image description here

answered Dec 3, 2013 at 11:18

Jaydipsinh Zala

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1 Comment

Charles Goodwin Over a year ago

This fixes the sample, hence I upvoted, but really the sample is flawed.

vipw · Accepted Answer · 2013-12-03 09:57:51Z

0

It looks like your JSONArray contains a JSONArray and a JSONObject. A JSONArray is not a JSONObject.

Are you in control of the source format? Because it looks a little weird.

The structure is as so: At position 0 is an array with one object, and a position 1 is an object.

Your code can be changed to this:

org.codehaus.jettison.json.JSONArray c = obj.getJSONArray("Channel_12");
JSONArray array = c.getJSONArray(0);
JSONObject obj2 = array.getJSONObject(0);

System.out.println(obj2.getString("to").toString());
System.out.println(obj2.getString("msg").toString());

answered Dec 3, 2013 at 9:57

vipw

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4 Comments

Alosyius Over a year ago

Getting: org.codehaus.jettison.json.JSONException: JSONArray[0] is not a JSONArray.

vipw Over a year ago

Can you prettyprint the c variable and see what it thinks is in it?

Alosyius Over a year ago

How can i accomplish that?

vipw Over a year ago

I suppose just clicking on it in the debugger would get you the info you need.

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