Java - looping through JSONArray

Question

i am trying to call an URL and afterwards to save the results of the URL into a database.

The call of the URL is working and i also am able to save the result into JSON objects/arrays.

This is my code so far:

JSONParser parser = new JSONParser();

try
{

    // responseString is the answer i get from calling the URL.
    // It's pretty long that's why i don't copy it in here now
    // But you can call this URL to see what the result is:
    // http://www.gw2spidy.com/api/v0.9/json/items/all/1?filter_ids=29169,29185


    Object objToParse = parser.parse(responseString);

    JSONObject jsonObject = (JSONObject) objToParse;

    JSONArray array = (JSONArray) jsonObject.get("results");

    // Until here everything is ok, the results get saved into the array

    JSONObject mJsonObject = new JSONObject();

    for (int i = 0; i < array.length() ; i++)
    {
        mJsonObject = (JSONObject)array.get(i);
        System.out.println(mJsonObject);
    }

}
catch(ParseException pe)
{
    System.out.println("position: " + pe.getPosition());
    System.out.println(pe);     
}

When i try to run this i get an error when i try to loop through the array:

 Exception in thread "main" java.lang.ClassCastException:     org.json.simple.JSONArray cannot be cast to java.lang.CharSequence

I already searched for solutions but i cannot find or understand what is causing the error for me, would be nice if someone can help me here..

Use code.google.com/p/google-gson, it might help you in future. It is intuitive and easy :) — Abhishek
– Abhishek, Commented Apr 4, 2015 at 12:31
Don't post answer inside question. Instead create separate answer for it under your question in answers section. Also avoid JSONArray array = (JSONArray) jsonObject.get("results");. Much more readable form is JSONArray array = jsonObject.getJSONArray("results");. Same about array.getJSONObject(i). — Pshemo
– Pshemo, Commented Apr 4, 2015 at 12:40

BlackOutDev · Accepted Answer · 2015-04-04 13:17:33Z

1

Ok at the end this was working for me:

JSONObject jsonObject = new JSONObject(responseString);
JSONArray array = (JSONArray) jsonObject.get("results");

JSONObject mJsonObject = new JSONObject();

for (int i = 0; i < array.length() ; i++)
{
    mJsonObject = (JSONObject)array.get(i);
    System.out.println(mJsonObject);



}

Had to change org.json.simple to instead use org.json and changed some lines then it was working.

answered Apr 4, 2015 at 13:17

BlackOutDev

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Comments

Ridcully · Accepted Answer · 2015-04-04 12:44:13Z

0

I rather think that your implementation using simple json was wrong. Although you didn't mention exactly, the only place your Exception could happen would be the line

JSONArray array = (JSONArray) jsonObject.get("results");

and as this is the same in both implementations, something previous to that must have happened leading to a situation with simple json where the results property is not a JSONArray. Probably something with parser.parse(...).

answered Apr 4, 2015 at 12:44

Ridcully

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2 Comments

BlackOutDev Over a year ago

The exception happened at this line: "for (int i = 0; i < array.length() ; i++)" Honestly i don't know if i missed something with simple.json , i just started developing java last week so i'm by far no pro, but now it's working and i don't think i will go back and try again with simple..

Ridcully Over a year ago

You probably won't go back to simple, but for the sake of learning Java (or anything other as well) it would be better to understand an error and not just try something different in the hope that it might work.

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