Converting JSONArray String to array

Question

I have this JSON data

{"mydata":{"numbers":[12,23,34]}}

By taking JSONObject I get following object:

JSONObject obj = mydataObj.getJSONObject("mydata");

So obj is this:

{"numbers":[12,23,34]}

I need to use the numbers elements. So I will make a for-loop to use elements.

String numbers = myObject.getString("numbers");

This gives a string like this:

["12","23","34"]

How can I convert this to an array or arraylist?
So I will have an array having values of 12, 23 and 34.

Edit: After getting the Array, ArrayList of JSONArray, I will compare "numbers1_Array" and "numbers2_Array". Then I will find the elements that exists in first array but doesn't exists in second array. So selecting data structure type related to which compare operation is easier.

Answer 1

You could try getJSONArray() instead of getString(), and then simply iterate over the JSONArray and build your ArrayList.

Answer 2

try this

   JSONArray jArray = jObj.getJSONArray("numbers");
   List list<Long> = new ArrayList<Long>(); 

    for(int i=0; i < jArray .length(); i++)
        list.add(new Long((String)jArray .get(i)));

Answer 3

after getting the object in JSONObject what you have is

JSONObject obj ===>>> {"numbers":[12,23,34]}

now this object is an array so you cant just access an array by passing name only you have to do something like this

JSONArray numbers = (JSONArray) jsonObject.get("numbers");
        Iterator<Integer> iterator = numbers.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next());
                    // this iterator.next() is your element from the JSON array
                    //you can store like 
                    // int val = iterator.next()
                    // better you store this in an array 
        }

Answer 4

Others solutions are fine, you can also do with your string like this

numbers=numbers.substring(1,s.length()-1).replaceAll("\"","");
List<String> sample = new ArrayList<String>();
sample.addAll(Arrays.asList(s.split(",")));

Answer 5

You could do it this way using Guava. https://github.com/google/guava

    String numbers = myObject.getString("numbers");
    List list = new ArrayList();
    JSONArray numbersJsonArray = new JSONArray(numbers);
    for (int i = 0; i < numbersJsonArray.length(); i ++) {
        list.add(numbersJsonArray.getInt(i));
    }// after this loop if what you need is the array list you have it all in the list


    int[] array = Ints.toArray(list); // if you need array of ints