How to send a JSON object over Request with Android?

Question

I want to send the following JSON text

{"Email":"[email protected]","Password":"123456"}

to a web service and read the response. I know to how to read JSON. The problem is that the above JSON object must be sent in a variable name jason.

How can I do this from android? What are the steps such as creating request object, setting content headers, etc.

Solution 1

Android doesn't have special code for sending and receiving HTTP, you can use standard Java code. I'd recommend using the Apache HTTP client, which comes with Android. Here's a snippet of code I used to send an HTTP POST.

I don't understand what sending the object in a variable named "jason" has to do with anything. If you're not sure what exactly the server wants, consider writing a test program to send various strings to the server until you know what format it needs to be in.

int TIMEOUT_MILLISEC = 10000;  // = 10 seconds
String postMessage="{}"; //HERE_YOUR_POST_STRING.
HttpParams httpParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParams, TIMEOUT_MILLISEC);
HttpConnectionParams.setSoTimeout(httpParams, TIMEOUT_MILLISEC);
HttpClient client = new DefaultHttpClient(httpParams);

HttpPost request = new HttpPost(serverUrl);
request.setEntity(new ByteArrayEntity(
    postMessage.toString().getBytes("UTF8")));
HttpResponse response = client.execute(request);

Solution 2

Sending a json object from Android is easy if you use Apache HTTP Client. Here's a code sample on how to do it. You should create a new thread for network activities so as not to lock up the UI thread.

    protected void sendJson(final String email, final String pwd) {
        Thread t = new Thread() {

            public void run() {
                Looper.prepare(); //For Preparing Message Pool for the child Thread
                HttpClient client = new DefaultHttpClient();
                HttpConnectionParams.setConnectionTimeout(client.getParams(), 10000); //Timeout Limit
                HttpResponse response;
                JSONObject json = new JSONObject();

                try {
                    HttpPost post = new HttpPost(URL);
                    json.put("email", email);
                    json.put("password", pwd);
                    StringEntity se = new StringEntity( json.toString());  
                    se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
                    post.setEntity(se);
                    response = client.execute(post);

                    /*Checking response */
                    if(response!=null){
                        InputStream in = response.getEntity().getContent(); //Get the data in the entity
                    }

                } catch(Exception e) {
                    e.printStackTrace();
                    createDialog("Error", "Cannot Estabilish Connection");
                }

                Looper.loop(); //Loop in the message queue
            }
        };

        t.start();      
    }

You could also use Google Gson to send and retrieve JSON.

Solution 3

public void postData(String url,JSONObject obj) {
    // Create a new HttpClient and Post Header

    HttpParams myParams = new BasicHttpParams();
    HttpConnectionParams.setConnectionTimeout(myParams, 10000);
    HttpConnectionParams.setSoTimeout(myParams, 10000);
    HttpClient httpclient = new DefaultHttpClient(myParams );
    String json=obj.toString();

    try {

        HttpPost httppost = new HttpPost(url.toString());
        httppost.setHeader("Content-type", "application/json");

        StringEntity se = new StringEntity(obj.toString()); 
        se.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
        httppost.setEntity(se); 

        HttpResponse response = httpclient.execute(httppost);
        String temp = EntityUtils.toString(response.getEntity());
        Log.i("tag", temp);


    } catch (ClientProtocolException e) {

    } catch (IOException e) {
    }
}

Solution 4

HttpPost is deprecated by Android Api Level 22. So, Use HttpUrlConnection for further.

public static String makeRequest(String uri, String json) {
    HttpURLConnection urlConnection;
    String url;
    String data = json;
    String result = null;
    try {
        //Connect 
        urlConnection = (HttpURLConnection) ((new URL(uri).openConnection()));
        urlConnection.setDoOutput(true);
        urlConnection.setRequestProperty("Content-Type", "application/json");
        urlConnection.setRequestProperty("Accept", "application/json");
        urlConnection.setRequestMethod("POST");
        urlConnection.connect();

        //Write
        OutputStream outputStream = urlConnection.getOutputStream();
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
        writer.write(data);
        writer.close();
        outputStream.close();

        //Read
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream(), "UTF-8"));

        String line = null;
        StringBuilder sb = new StringBuilder();

        while ((line = bufferedReader.readLine()) != null) {
            sb.append(line);
        }

        bufferedReader.close();
        result = sb.toString();

    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return result;
}

Solution 5

There's a surprisingly nice library for Android HTTP available at the link below:

http://loopj.com/android-async-http/

Simple requests are very easy:

AsyncHttpClient client = new AsyncHttpClient();
client.get("http://www.google.com", new AsyncHttpResponseHandler() {
    @Override
    public void onSuccess(String response) {
        System.out.println(response);
    }
});

To send JSON (credit to `voidberg' at https://github.com/loopj/android-async-http/issues/125):

// params is a JSONObject
StringEntity se = null;
try {
    se = new StringEntity(params.toString());
} catch (UnsupportedEncodingException e) {
    // handle exceptions properly!
}
se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));

client.post(null, "www.example.com/objects", se, "application/json", responseHandler);

It's all asynchronous, works well with Android and safe to call from your UI thread. The responseHandler will run on the same thread you created it from (typically, your UI thread). It even has a built-in resonseHandler for JSON, but I prefer to use google gson.

View more solutions

Comments

[AndroidDev]

Hi could it be possible that the server requires me to set a header caled JSON and put the json content in that header ? I sending the url as HttpPost post=new HttpPost("abc.com/xyz/usersgetuserdetails"); But its saying invalid request error. The remiander of the code is the same. Secondly what does json = header = new JSONObject(); Whats happening here

[AndroidDev]

Is postMessage an JSON object ?

[Primal Pappachan]

I'm not sure what kind of request is expected by the server. As for this ' json = header = new JSONObject(); ' it's just creating 2 json objects.

[kubiej21]

@primpop - Is there any chance that you might be able to provide a simple php script to go along with this? I tried implementing your code, but I for the life of me could not get it to send anything other than NULL.

[Yekmer Simsek]

you can get the output from inputsputstream(in object here) as string like this StringWriter writer = new StringWriter(); IOUtils.copy(in, writer, "UTF-8"); String theString = writer.toString();

[Karthick]

I have post the json object to ASP.Net mvc server. How can I query the same json string in ASP.Net server.?

[Raptor]

postMessage is not defined

[Lion789]

what is the timeout for?

[Mayur R. Amipara]

what if passing more than one string? like postMessage2.toString().getBytes("UTF8")

[Esko918]

Do you know the minimum sdk this runs on?

[Alex]

I'd be surprised if it had a minimum since it's not GUI. Why not try it out and post your findings.

[Esko918]

Well i decided to use the native libraries instead. Theres more informatoin about that and since im fairly new to android. Im really a iOS dev. Its better since im reading up on all the docs instead of just plugging and playing with someone elses code. Thanks though

[tgkprog]

Suggestions to convert a POJO to Json string?

[Dabbler]

Upvoted for pointing to okhttp, which is a useful library, but the code as given does not help much. For example, what are the arguments passed to RequestBody.create()? See this link for more details: vogella.com/tutorials/JavaLibrary-OkHttp/article.html

[CoderBC]

The accepted answer is depreciated and this approach is better

[tony gil]

currently deprecated, unfortunately. :(