HTTPResponse as JSON in Java

Question

I was trying to get an JSONObject from a HTTP response.

try
    {   
        GetMethod postMethod = new GetMethod();
        postMethod.setURI(new URI(url, true));
        postMethod.setRequestHeader("Accept", "application/json");
        httpClient.executeMethod(postMethod);
        String resp=postMethod.getResponseBodyAsString();
        org.json.JSONTokener tokener = new org.json.JSONTokener(resp);
        finalResult = new org.json.JSONArray(tokener);

        return finalResult;
    }

But I got a runtime warning as

Going to buffer response body of large or unknown size. Using getResponseBodyAsStream instead is recommended.

Should I get the response as stream as suggested by the JVM ? If so, how could I parse the JSON from it ?

Just read the content to a byte[], turn that byte[] into a String (depending on the encoding) and parse that String as JSON — fge
– fge, Commented Jun 19, 2013 at 12:39
I would hope that one of the several dozen JSON packages for Java can read directly from a stream. — Hot Licks
– Hot Licks, Commented Jan 29, 2014 at 1:41

Mike 'Pomax' Kamermans · Accepted Answer · 2013-06-19 13:07:35Z

3

Has your server been set up to inform clients how big its responses are? If not, your server is streaming the data, and it's technically impossible to tell how much buffer space is required to deal with the response, warranting a warning that something potentially dangerous is going on.

answered Jun 19, 2013 at 13:07

Mike 'Pomax' Kamermans

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Tiny · Accepted Answer · 2014-01-29 02:57:08Z

if you want to send jsonObjects from server suppose (tomcat server)

For server side-

creating jsonobjects-

I have Called toJson() for creating jsonobjects this is the implementation-

final JSONObject arr = new JSONObject();

for (int i = 0; i < contactStatus.size(); i++) {
    ContactStatus contactObject = contactStatus.get(i);

    try {
        arr.put(String.valueOf(i), toJson(value1, value2,, value3));
    } catch (JSONException e) {

     catch block e.printStackTrace();
    }
}

//Here we serialize the stream to a String.
final String output = arr.toString();
response.setContentLength(output.length());
out.print(output);//out is object of servlet output stream.

public static Object toJsonForContact(String value1, boolean value2, double value3) throws JSONException {

    JSONObject contactObject = new JSONObject();
    contactObject.put("id", id);
    contactObject.put("status", value1);
    contactObject.put("distance", value2);
    contactObject.put("relation", value3);
    return contactObject;
}

so your jsonobjects are ready for sending we write these objects to ServletoutputStream.

in client side-

while ((ReadResponses = in.readLine()) != null) {
        Constants.Response_From_server = ReadResponses;

        if (Constants.Response_From_server.startsWith("{")) {
            ListOfContactStatus = new ArrayList<ContactStatus>();
            ContactStatus contactStatusObject;

            try {
                JSONObject json = new JSONObject(Constants.Response_From_server);

                for (int i = 0; i < json.length(); i++) {
                    contactStatusObject = new ContactStatus();

                    JSONObject json1 = json.getJSONObject(String.valueOf(i));
                    System.out.println("" + json1.getString("id"));
                    System.out.println("" + json1.getBoolean("status"));
                    System.out.println("" + json1.getDouble("distance"));

                    contactStatusObject.setId(json1.getString("id"));
                    contactStatusObject.setStatus(json1.getBoolean("status"));
                    contactStatusObject.setDistance((float) json1.getDouble("distance"));
                    ListOfContactStatus.add(contactStatusObject);
                    System.out.println("HTTPTransport:sendMessage  Size of ListOfContactStatus" + ListOfContactStatus.size());
                }
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
}

Masudul · Accepted Answer · 2013-06-20 11:00:59Z

1

You can easily generate JSonObject usin Java EE 7. The sample code.

    JsonReader reader = Json.createReader(new URI(url, true));
    JsonObject jsonObject=reader.readObject();

For details information go through to the link. http://docs.oracle.com/javaee/7/tutorial/doc/jsonp003.htm#BABHAHIA

answered Jun 20, 2013 at 11:00

Masudul

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