Send JSon from Server to Client in GCM - google-app-engine

Question

I am Using GCM (Google Cloud Messaging).In that what i want i want to send J Son from the server side .On Client side I want to receive that for simple message i have done but i am stucked how could i pass J Son from the server side to the client side.
Please help me to resolve this.
This is my Server side code
public class GCMBroadcast extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final String SENDER_ID = "";
private static final String ANDROID_DEVICE = "";
private List<String> androidTargets = new ArrayList<String>();
public GCMBroadcast() {
super();
androidTargets.add(ANDROID_DEVICE);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String collapseKey = "";
String userMessage = "";
try {
userMessage = request.getParameter("Message");
collapseKey = request.getParameter("CollapseKey");
} catch (Exception e) {
e.printStackTrace();
return;
}
Sender sender = new Sender(SENDER_ID);
Message message = new Message.Builder()
.collapseKey(collapseKey)
.addData("message", userMessage)
.build();
try {
MulticastResult result = sender.send(message, androidTargets, 1);
System.out.println("Response: " + result.getResults().toString());
if (result.getResults() != null) {
int canonicalRegId = result.getCanonicalIds();
if (canonicalRegId != 0) {
System.out.println("response " +canonicalRegId );
}
} else {
int error = result.getFailure();
System.out.println("Broadcast failure: " + error);
}
} catch (Exception e) {
e.printStackTrace();
}
request.setAttribute("CollapseKey", collapseKey);
request.setAttribute("Message", userMessage);
request.getRequestDispatcher("XX.jsp").forward(request, response);
}
}

Answer 1

Your payload (added to the Message by calls to addData) can only be name/value pairs. If you want to send a JSON, you can put a JSON string in the value of such name/value pair. Then you'll have to parse that JSON yourself in the client side.
For example :
.addData("message","{\"some_json_key\":\"some_json_value\"}")