简体   繁体   中英

Java - looping through JSONArray

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..

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.

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(...) .

The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.

 
粤ICP备18138465号  © 2020-2024 STACKOOM.COM