Question

my web service returns json encoded data to my java application.. how to make the java application read the json_encoded data properly? for example, the returned data looks like this
{“necessities”:-18,”fun”:26,”education”:0.6,”give”:0,”ffa”:3.8,”ltss”:909.6,”message”:array{“1″:33,”2”:44}}
as you can see there’s some nested data inside that.. how can I make the java apps reads the returned string with something like this (if it’s being done in php instead)
echo returndata[“necessities”] and it displays -18
echo returndata[“message”][“1”] and it displays 33

Answer 1

In Java everything is an object, so you need to build an object(s) from this JSON string.
You can use this small library:
http://json.org/java/
With that, you are able to build JSONObjects, JSONArrays, etc. and extract all the information you wanted.
Here you have an example:

/**
 * Constructs feed items based on the JSON string.
 * 
 * @param response String containing JSON with feed items array.
 * @throws JSONException
 */
public FeedItems(String response) throws JSONException
{
    JSONObject json = new JSONObject(response);
    JSONArray items = json.getJSONArray("items");
    for (int i = 0; i < items.length(); i++)
    {
        JSONObject feedItemObject = items.getJSONObject(i);
        String id = feedItemObject.getString("id");
        String title = feedItemObject.getString("title");
        FeedItem feedItem = new FeedItem(id, title);
        feedItems.add(feedItem);
    }
}