REST in a J2ME/Java ME application

[Infms]

Hi everyone,

What would be the best way to consume a REST service in a J2ME/Java ME application? Data is in JSON format. Unfortunately there don't seem to be any helper libraries available.

Many thanks

[marcelobarrosalmeida]

Hello Infms !

I am using https://github.com/upictec/org.json.me/, with success, for a REST/JSON service.
The usage is straightforward, just download the buffer and decode it using json parser.

    // downloading ....
    public boolean Response20X(HttpConnection connection, Hashtable cookies) {
        
        boolean result = false;
        StringBuffer strf = null;
        response = null;
        
        try {
            InputStream is = connection.openInputStream();
            InputStreamReader isr = new InputStreamReader(is, "UTF-8");

            int ch;
            strf = new StringBuffer();
            while ((ch = isr.read()) != -1) {
                strf.append((char) ch);
            }
            
            response = strf.toString();
            strf = null;
            // TODO do not decode before checking reponse code
            result = data.fromJSONString(response);
            response = null;
            isr.close();
            is.close();
            
        } catch (IOException ex) {
            ex.printStackTrace();
        }

        return result;
    }

        // decoding ....
	public boolean fromJSONString(String str) {
        boolean result = false;
        
        try {
            Vector _data = new Vector();
            JSONObject jobj = new JSONObject(str);
            JSONArray feeds = jobj.getJSONArray("data");
            
            if(feeds != null) {
                for(int n = 0 ; n < feeds.length(); n++) {
                    // more decoding ...
                }
            }
            result = true;
            
        } catch (JSONException ex) {
            ex.printStackTrace();
        }
        
        return result;
    }

Marcelo Barros

[Infms]

Hi Marcelo,

Thanks for the reply and example code. Say for example I had a REST service I wanted to access at htt://alpha.myrestservice.com/ and send the request: GET api/lists

How would I go about using the library to send such a request?

Thanks

[marcelobarrosalmeida]

The request should be done via some HttpConnection call. For instance:

String url = "https://api.instagram.com/v1/users/self/feed";

HttpConnection connection = (HttpConnection) Connector.open(url,Connector.READ_WRITE,true);
connection.setRequestMethod(HttpConnection.GET);
connection.setRequestProperty("User-Agent", "Mozilla/5.0 (Series40)");
connection.setRequestProperty("Connection", "close");          
int code = connection.getResponseCode();

if(code == HttpConnection.HTTP_OK) {
	// handle result, read data ...
} else {
/// ...            
}
connection.close();

Check the demo "PicasaViewer" for another example: http://is.gd/JmLsV8

See you
Marcelo Barros

[marcelobarrosalmeida]

Moreover, have you tried Tantalum ? It seems pretty good.

https://projects.developer.nokia.com/Tantalum

"Simplified XML and JSON parsing into value objects"

We will give it a try ASAP.

Marcelo Barros

[Infms]

I ended up using the Tantalum library (for handling JSON) along with the HttpConnection GET request, similar to what you posted below. Everything works great! Thanks again