Converting JSONObject to JSONArray Exception

Question

I have a website that I have to make queries on in Java. Here you can see the dataset

https://www.quandl.com/api/v3/datasets/SSE/HYQ.json?start_date=2017-01-01&end_date=2017-01-31

At the very first beginning, I thought this is a JSONArray, but Eclipse always told me, it is not.

So therefore I tried to convert from JSONObject to JSONArray but I get this error:

org.json.JSONException: JSONObject["dataset"] is not a JSONArray.

What am I doing wrong?

Here is my code:

package query;

 import java.net.URL;
 import java.net.URLConnection;
 import java.nio.charset.Charset;

 import java.util.*;
 import java.io.*;
 import org.json.JSONArray;
 import org.json.JSONException;
 import org.json.JSONObject;

public class Stockquery {

public static void main(String[] args) {

    String jsonString = callURL(
            "https://www.quandl.com/api/v3/datasets/SSE/HYQ.json?start_date=2017-01-01&end_date=2017-01-31");
    // System.out.println("\n\njsonString: " + jsonString);

    try {
        JSONObject jsonobjects = new JSONObject(jsonString);
        System.out.println("\n\njsonArray: " + jsonobjects);
        JSONArray arr = jsonobjects.getJSONArray("dataset");

        for (int i = 0; i < arr.length(); i++) {
            JSONObject obj = arr.getJSONObject(i); 
            System.out.println(obj);
        }

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

}

public static String callURL(String myURL) {
    // System.out.println("Requested URL:" + myURL);
    StringBuilder sb = new StringBuilder();
    URLConnection urlConn = null;
    InputStreamReader in = null;
    try {
        URL url = new URL(myURL);
        urlConn = url.openConnection();
        if (urlConn != null)
            urlConn.setReadTimeout(60 * 1000);
        if (urlConn != null && urlConn.getInputStream() != null) {
            in = new InputStreamReader(urlConn.getInputStream(), Charset.defaultCharset());
            BufferedReader bufferedReader = new BufferedReader(in);
            if (bufferedReader != null) {
                int cp;
                while ((cp = bufferedReader.read()) != -1) {
                    sb.append((char) cp);
                }
                bufferedReader.close();
            }
        }
        in.close();
    } catch (Exception e) {
        throw new RuntimeException("Exception while calling URL:" + myURL, e);
    }

    return sb.toString();
}

}

dataset is jsonobject , what exactly your want to do with your response — Pavneet_Singh
– Pavneet_Singh, Commented Jun 26, 2017 at 18:04

Pavneet_Singh · Accepted Answer · 2017-06-26 18:15:36Z

2

The dataset field of jsonobjects is a JSONObject not JSONArray. Change this:

jsonobjects.getJSONArray("dataset");

to this:

JSONObject dataset = jsonobjects.getJSONObject("dataset");
JSONArray array    = dataset.getJSONArray("data");

edited Jun 26, 2017 at 18:15

Pavneet_Singh

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answered Jun 26, 2017 at 18:05

Alvin Abia

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3 Comments

Alvin Abia Over a year ago

Are you sure? I just printed the JSON locally and 'data' is a JSONArray of JSONArrays in the 'dataset' JSONObject

Blnpwr Over a year ago

Could you copy your code in your answer please, so that I can check what I missed, I have lost the red thread.

Blnpwr Over a year ago

Yeah, now it works, thanks for the edit and for the answer of course :)

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