[java] Using HttpClient and HttpPost in Android with post parameters

I'm writing code for an Android application that is supposed to take data, package it as Json and post it to a web server, that in turn is supposed to respond with json.

Using a GET request works fine, but for some reason using POST all data seems to get stripped and the server does not receive anything.

Here's a snippet of the code:

HttpParams params = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(params, 5000);
HttpConnectionParams.setSoTimeout(params, 5000);        
DefaultHttpClient httpClient = new DefaultHttpClient(params);
BasicCookieStore cookieStore = new BasicCookieStore();
httpClient.setCookieStore(cookieStore);

String uri = JSON_ADDRESS;
String result = "";
String username = "user";
String apikey = "something";
String contentType = "application/json";

JSONObject jsonObj = new JSONObject();

try {
    jsonObj.put("username", username);
    jsonObj.put("apikey", apikey);
} catch (JSONException e) {
    Log.e(TAG, "JSONException: " + e);
}

HttpPost httpPost = new HttpPost(uri);
List<NameValuePair> postParams = new ArrayList<NameValuePair>();
postParams.add(new BasicNameValuePair("json", jsonObj.toString()));
HttpGet httpGet = null;
try {
    UrlEncodedFormEntity entity = new UrlEncodedFormEntity(postParams);
    entity.setContentEncoding(HTTP.UTF_8);
    entity.setContentType("application/json");
    httpPost.setEntity(entity);

    httpPost.setHeader("Content-Type", contentType);
    httpPost.setHeader("Accept", contentType);
} catch (UnsupportedEncodingException e) {
    Log.e(TAG, "UnsupportedEncodingException: " + e);
}

try {
    HttpResponse httpResponse = httpClient.execute(httpPost);
    HttpEntity httpEntity = httpResponse.getEntity();

    if (httpEntity != null) {
        InputStream is = httpEntity.getContent();
        result = StringUtils.convertStreamToString(is);
        Log.i(TAG, "Result: " + result);
    }
} catch (ClientProtocolException e) {
    Log.e(TAG, "ClientProtocolException: " + e);
} catch (IOException e) {
    Log.e(TAG, "IOException: " + e);
}

return result;

I think I have followed the general guidelines on how to create the parameters and post them, but apparently not.

Any help or pointers to where I can find a solution, are very welcome at this point (after spending a few hours realizing no post data was ever sent). The real server is running Wicket on Tomcat, but I've also tested it out on a simple PHP page, with no difference.

I've just checked and i have the same code as you and it works perferctly. The only difference is how i fill my List for the params :

I use a : ArrayList<BasicNameValuePair> params

and fill it this way :

 params.add(new BasicNameValuePair("apikey", apikey);

I do not use any JSONObject to send params to the webservices.

Are you obliged to use the JSONObject ?

You can actually send it as JSON the following way:

// Build the JSON object to pass parameters
JSONObject jsonObj = new JSONObject();
jsonObj.put("username", username);
jsonObj.put("apikey", apikey);
// Create the POST object and add the parameters
HttpPost httpPost = new HttpPost(url);
StringEntity entity = new StringEntity(jsonObj.toString(), HTTP.UTF_8);
entity.setContentType("application/json");
httpPost.setEntity(entity);
HttpClient client = new DefaultHttpClient();
HttpResponse response = client.execute(httpPost);

public class GetUsers extends AsyncTask {

    @Override
    protected void onPreExecute() {
        super.onPreExecute();

    }

    private String convertStreamToString(InputStream is) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        return sb.toString();
    }

    public String connect()
    {
        HttpClient httpclient = new DefaultHttpClient();

        // Prepare a request object
        HttpPost htopost = new HttpPost("URL");
        htopost.setHeader(new BasicHeader("Authorization","Basic Og=="));

        try {

            JSONObject param = new JSONObject();
            param.put("PageSize",100);
            param.put("Userid",userId);
            param.put("CurrentPage",1);

            htopost.setEntity(new StringEntity(param.toString()));

            // Execute the request
            HttpResponse response;

            response = httpclient.execute(htopost);
            // Examine the response status
            // Get hold of the response entity
            HttpEntity entity = response.getEntity();

            if (entity != null) {

                // A Simple JSON Response Read
                InputStream instream = entity.getContent();
                String result = convertStreamToString(instream);

                // A Simple JSONObject Creation
                json = new JSONArray(result);

                // Closing the input stream will trigger connection release
                instream.close();
                return ""+response.getStatusLine().getStatusCode();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return null;
    }

    @Override
    protected String doInBackground(String... urls) {
        return connect();
    }

    @Override
    protected void onPostExecute(String status){
        try {

            if(status.equals("200"))
            {

                    Global.defaultMoemntLsit.clear();

                    for (int i = 0; i < json.length(); i++) {
                        JSONObject ojb = json.getJSONObject(i);
                        UserMomentModel u = new UserMomentModel();
                        u.setId(ojb.getString("Name"));
                        u.setUserId(ojb.getString("ID"));


                        Global.defaultMoemntLsit.add(u);
                    }




                            userAdapter = new UserAdapter(getActivity(), Global.defaultMoemntLsit);
                            recycleView.setAdapter(userMomentAdapter);
                            recycleView.setLayoutManager(mLayoutManager);
           }



        }
        catch (Exception e)
        {
            e.printStackTrace();

        }
    }
}