Sending Complex JSON Object

Question

I want to communicate with a web server and exchange JSON information.

my webservice URL looking like following format: http://46.157.263.140/EngineTestingWCF/DPMobileBookingService.svc/SearchOnlyCus

Here is my JSON Request format.

{
    "f": {
        "Adults": 1,
        "CabinClass": 0,
        "ChildAge": [
            7
        ],
        "Children": 1,
        "CustomerId": 0,
        "CustomerType": 0,
        "CustomerUserId": 81,
        "DepartureDate": "/Date(1358965800000+0530)/",
        "DepartureDateGap": 0,
        "Infants": 1,
        "IsPackageUpsell": false,
        "JourneyType": 2,
        "PreferredCurrency": "INR",
        "ReturnDate": "/Date(1359138600000+0530)/",
        "ReturnDateGap": 0,
        "SearchOption": 1
    },
    "fsc": "0"
}

I tried with the following code to send a request:

public class Fdetails {
    private String Adults = "1";
    private String CabinClass = "0";
    private String[] ChildAge = { "7" };
    private String Children = "1";
    private String CustomerId = "0";
    private String CustomerType = "0";
    private String CustomerUserId = "0";
    private Date DepartureDate = new Date();
    private String DepartureDateGap = "0";
    private String Infants = "1";
    private String IsPackageUpsell = "false";
    private String JourneyType = "1";
    private String PreferredCurrency = "MYR";
    private String ReturnDate = "";
    private String ReturnDateGap = "0";
    private String SearchOption = "1";
}

public class Fpack {
    private Fdetails f = new Fdetails();
    private String fsc = "0";
}

Then using Gson I create the JSON object like:

public static String getJSONString(String url) {
String jsonResponse = null;
String jsonReq = null;
Fpack fReq = new Fpack();

try {                                                
    Gson gson = new Gson();
    jsonReq = gson.toJson(fReq);                        
    JSONObject json = new JSONObject(jsonReq);
    JSONObject jsonObjRecv = HttpClient.SendHttpPost(url, json);
    jsonResponse = jsonObjRecv.toString();
} 
catch (JSONException e) {
                           e.printStackTrace();
                }               
return jsonResponse;
    }

and my HttpClient.SendHttpPost method is

public static JSONObject SendHttpPost(String URL, JSONObject json) {

        try {
            DefaultHttpClient httpclient = new DefaultHttpClient();
            HttpPost httpPostRequest = new HttpPost(URL);

            StringEntity se;
            se = new StringEntity(json.toString());
            httpPostRequest.setEntity(se);
            se.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));          
            HttpResponse response = (HttpResponse) httpclient.execute(httpPostRequest);
            HttpEntity entity = response.getEntity();
            if (entity != null) {
                // Read the content stream
                InputStream instream = entity.getContent();
                Header contentEncoding = response.getFirstHeader("Content-Encoding");
                if (contentEncoding != null && contentEncoding.getValue().equalsIgnoreCase("gzip")) {
                    instream = new GZIPInputStream(instream);
                }

                // convert content stream to a String
                String resultString= convertStreamToString(instream);
                instream.close();
                resultString = resultString.substring(1,resultString.length()-1); // remove wrapping "[" and "]"

                // Transform the String into a JSONObject
                JSONObject jsonObjRecv = new JSONObject(resultString);
            return jsonObjRecv;
            } 
    catch (Exception e)
        {
            e.printStackTrace();
        }
        return null;
    }

Now I get the following exception:

org.json.JSONException: Value !DOCTYPE of type java.lang.String cannot be converted to JSONObject
at org.json.JSON.typeMismatch(JSON.java:111)
at org.json.JSONObject.<init>(JSONObject.java:158)
at org.json.JSONObject.<init>(JSONObject.java:171)

and the printout of JSON string right before I make the request is as follows:

{
    "f": {
        "PreferredCurrency": "MYR",
        "ReturnDate": "",            
        "ChildAge": [
            7
        ],
        "DepartureDate": "Mar 2, 2013 1:17:06 PM",
        "CustomerUserId": 0,
        "CustomerType": 0,
        "CustomerId": 0,
        "Children": 1,
        "DepartureDateGap": 0,
        "Infants": 1,
        "IsPackageUpsell": false,
        "JourneyType": 1,
        "CabinClass": 0,
        "Adults": 1,
        "ReturnDateGap": 0,
        "SearchOption": 1

    },
    "fsc": "0"
}

How do I solve this exception? Thanks in advance!

Answer 1

I'm not quite familiar with Json, but I know it's pretty commonly used today, and your code seems no problem.

How to convert this JSON string to JSON object?

Well, you almost get there, just send the JSON string to your server, and use Gson again in your server:

Gson gson = new Gson();
Fpack f = gson.fromJSON(json, Fpack.class);

http://google-gson.googlecode.com/svn/trunk/gson/docs/javadocs/index.html

About the Exception:

You should remove this line, because you are sending a request, not responsing to one:

httpPostRequest.setHeader("Accept", "application/json");

And I would change this line:

httpPostRequest.setHeader("Content-type", "application/json"); 

to

se.setContentEncoding(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));

If this doesn't make any difference, please print out your JSON string before you send the request, let's see what's in there.

Answer 2

To create a request with JSON object attached to it what you should do is the following:

public static String sendComment (String commentString, int taskId, String    sessionId, int displayType, String url) throws Exception
{
    Map<String, Object> jsonValues = new HashMap<String, Object>();
    jsonValues.put("sessionID", sessionId);
    jsonValues.put("NewTaskComment", commentString);
    jsonValues.put("TaskID" , taskId);
    jsonValues.put("DisplayType" , displayType);
    JSONObject json = new JSONObject(jsonValues);

    DefaultHttpClient client = new DefaultHttpClient();

    HttpPost post = new HttpPost(url + SEND_COMMENT_ACTION);

    AbstractHttpEntity entity = new ByteArrayEntity(json.toString().getBytes("UTF8"));
    entity.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
    post.setEntity(entity);
    HttpResponse response = client.execute(post);

    return getContent(response);    
}

Answer 3

From what I have understood you want to make a request to the server using the JSON you have created, you can do something like this:

URL url;
    HttpURLConnection connection = null;
    String urlParameters ="json="+ jsonSend;  
    try {
      url = new URL(targetURL);
      connection = (HttpURLConnection)url.openConnection();
      connection.setRequestMethod("POST");
      connection.setRequestProperty("Content-Type", 
           "application/x-www-form-urlencoded");
      connection.setRequestProperty("Content-Language", "en-US");  
      DataOutputStream wr = new DataOutputStream (
                  connection.getOutputStream ());
      wr.writeBytes (urlParameters);
      wr.flush ();
      wr.close ();

      InputStream is = connection.getInputStream();
      BufferedReader rd = new BufferedReader(new InputStreamReader(is));
      String line;
      StringBuffer response = new StringBuffer(); 
      while((line = rd.readLine()) != null) {
        response.append(line);
        response.append('\r');
      }
      rd.close();
      return response.toString();

    } catch (Exception e) {

      e.printStackTrace();
      return null;

    } finally {

      if(connection != null) {
        connection.disconnect(); 
      }
    }
  }

Answer 4

Actually it was a BAD REQUEST. Thats why server returns response as XML format. The problem is to convert the non primitive data(DATE) to JSON object.. so it would be Bad Request.. I solved myself to understand the GSON adapters.. Here is the code I used:

try {                                                       
                        JsonSerializer<Date> ser = new JsonSerializer<Date>() {

                            @Override
                            public JsonElement serialize(Date src, Type typeOfSrc,
                                    JsonSerializationContext comtext) {

                                return src == null ? null : new JsonPrimitive("/Date("+src.getTime()+"+05300)/");
                            }
                        };
                        JsonDeserializer<Date> deser = new JsonDeserializer<Date>() {                           
                            @Override
                            public Date deserialize(JsonElement json, Type typeOfT,
                                    JsonDeserializationContext jsonContext) throws JsonParseException {

                                String tmpDate = json.getAsString();

                                  Pattern pattern = Pattern.compile("\\d+");
                                  Matcher matcher = pattern.matcher(tmpDate);
                                  boolean found = false;

                                  while (matcher.find() && !found) {
                                       found = true;
                                        tmpDate = matcher.group();
                                  }
                                return json == null ? null : new Date(Long.parseLong(tmpDate));                             
                            }
                        };