Getting value from an array in a JSON Object in Java?

Question

I'm fairly new to REST API calls in Java and I'm currently encountering problems with trying to get the "item" section from the JSON object (below). I guess it also confuses me that "response" is an object in an array too?/

The JSON file is below:

{
"version": "1.0",
"code": 200,
"request":{"text":["seafood" ], "lang": "en", "type": "stimulus"},
"response":[{
    "text": "seafood",
    "items":[
         {"item": "Shrimp", "weight": 100, "pos": "noun" }, 
         {"item": "Lobster",…
     ]
}]
}

I have currently managed to get the "response" part of the object using:

BufferedReader in = new BufferedReader( 
    new InputStreamReader(conection.getInputStream()));
StringBuffer json = new StringBuffer();
while ((readLine = in.readLine()) != null) {
    json.append(readLine);
} 
in.close();
JSONParser parser = new JSONParser();
try{
    JSONObject object= (JSONObject) parser.parse(json.toString());
    Object response = json.get("response");
...

Up to this point, I get stuck. I don't know what to do to 'response' to get to "items", and if I try to cast 'response' as a JSONObject, it will return as null?

What I want to try and do is to get each "item" in the "items" part and put it in a list.

Help would be very much appreciated!

Answer 1

I think it should works:

JSONParser parser = new JSONParser();
try{
    JSONObject object= (JSONObject) parser.parse(json.toString());
    JSONArray response = object.getJSONArray("response");
    JSONObject responseObject = response.getJSONObject(0);
    JSONArray expectedArray = responseObject.getJSONArray("items");
    for (int i = 0; i < expectedArray.length(); i++) {
        String item = expectedArray.getJSONObject(i).getString("item");
        String weight = expectedArray.getJSONObject(i).getInt("weight");
        ......
        //Here you can create your custom object and add to your array. For example
        list.add(new MyOwnObject(item, weight));
    }
....

Because response is array, not object

Answer 2

You should check the documentation for JSONObject . It describes all of the methods which are available. Note that there is no method named get() . Instead, you probably want to use getJSONArray()