In this answer I am using an example posted by Justin Grammens.

About JSON

JSON stands for JavaScript Object Notation. In JavaScript properties can be referenced both like this object1.name and like this object['name'];. The example from the article uses this bit of JSON.

The Parts
A fan object with email as a key and foo@bar.com as a value

{  fan:    {      email : 'foo@bar.com'    }}

So the object equivalent would be fan.email; or fan['email'];. Both would have the same value of 'foo@bar.com'.

About HttpClient Request

The following is what our author used to make a HttpClient Request. I do not claim to be an expert at all this so if anyone has a better way to word some of the terminology feel free.

public static HttpResponse makeRequest(String path, Map params) throws Exception {    //instantiates httpclient to make request    DefaultHttpClient httpclient = new DefaultHttpClient();    //url with the post data    HttpPost httpost = new HttpPost(path);    //convert parameters into JSON object    JSONObject holder = getJsonObjectFromMap(params);    //passes the results to a string builder/entity    StringEntity se = new StringEntity(holder.toString());    //sets the post request as the resulting string    httpost.setEntity(se);    //sets a request header so the page receving the request    //will know what to do with it    httpost.setHeader("Accept", "application/json");    httpost.setHeader("Content-type", "application/json");    //Handles what is returned from the page     ResponseHandler responseHandler = new BasicResponseHandler();    return httpclient.execute(httpost, responseHandler);}

Map

If you are not familiar with the Map data structure please take a look at the Java Map reference. In short, a map is similar to a dictionary or a hash.

private static JSONObject getJsonObjectFromMap(Map params) throws JSONException {    //all the passed parameters from the post request    //iterator used to loop through all the parameters    //passed in the post request    Iterator iter = params.entrySet().iterator();    //Stores JSON    JSONObject holder = new JSONObject();    //using the earlier example your first entry would get email    //and the inner while would get the value which would be 'foo@bar.com'     //{ fan: { email : 'foo@bar.com' } }    //While there is another entry    while (iter.hasNext())     {        //gets an entry in the params        Map.Entry pairs = (Map.Entry)iter.next();        //creates a key for Map        String key = (String)pairs.getKey();        //Create a new map        Map m = (Map)pairs.getValue();           //object for storing Json        JSONObject data = new JSONObject();        //gets the value        Iterator iter2 = m.entrySet().iterator();        while (iter2.hasNext())         {            Map.Entry pairs2 = (Map.Entry)iter2.next();            data.put((String)pairs2.getKey(), (String)pairs2.getValue());        }        //puts email and 'foo@bar.com'  together in map        holder.put(key, data);    }    return holder;}