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;
}
Please feel free to comment on any questions that arise about this post or if I have not made something clear or if I have not touched on something that your still confused about... etc whatever pops in your head really.
(I will take down if Justin Grammens does not approve. But if not then thanks Justin for being cool about it.)
Update
I just happend to get a comment about how to use the code and realized that there was a mistake in the return type. The method signature was set to return a string but in this case it wasnt returning anything. I changed the signature to HttpResponse and will refer you to this link on Getting Response Body of HttpResponse the path variable is the url and I updated to fix a mistake in the code.
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