Extracting data from JSON array

Question

I know its an array, but I am completely new to JSON and need help comprehending how this is structured, here is my attempt at extracting data:

String JSonString = readURL("//my URL is here");
JSONArray s = JSONArray.fromObject(JSonString);
JSONObject Data =(JSONObject)(s.getJSONObject(0));
System.out.println(Data.get("name"));

My JSON data that I have goes like this :

 {
"sports": [
    {
        "name": "basketball",
        "id": 40,
        "uid": "s:40",
        "leagues": [
            {
                "name": "National Basketball Assoc.",
                "abbreviation": "nba",
                "id": 46,
                "uid": "s:40~l:46",
                "groupId": 7,
                "shortName": "NBA",
                "athletes": []
            }
        ]
    }
],
"resultsOffset": 10,
"resultsLimit": 10,
"resultsCount": 1,
"timestamp": "2013-11-18T03:15:43Z",
"status": "success"
}

I dont really have a strong grasp of this stuff so all the help is appreciated.

Answer 1

Here is the idea :

JSONObject root = new JSONObject(yourJsonString);
JSONArray sportsArray = root.getJSONArray("sports");

// now get the first element:
JSONObject firstSport = sportsArray.getJSONObject(0);

// and details of the first element
String name = firstSport.getString("name"); // basketball
int id = firstSport.getInt("id"); // 40
JSONArray leaguesArray = firstSport.getJSONArray("leagues");

// and so on, you can process leaguesArray similarly

It should work (feel free to complain about compile errors if there are any)

Answer 2

Your JSON data is an object (it starts with a curly brace). In the next inner layer, there is a single array (at key "sports"):

String jsonString = readURL("//my URL is here");
JSONObject result = JSONObject(jsonString);
JSONArray sports = result.getJSONArray("sports");
JSONObject sport = sport.getJSONObject(0);
System.out.println(sport.getString("name"));

I might have used another JSON library than you.

Answer 3

JSON means JavaScript Object Notation.

Objects in javascripts are just containers and can be represented by key-value pairs. Please find below notations to understand about json.

Represent objects in json: Eg Student

{"name" : "Robin", "rollnumber" : "1"}

Represent array in json : Eg Array of students

[{"name" : "Robin", "rollnumber" : "1"}, {"name" : "Mark", "rollnumber" : "2"}]

You can understand more on JSON from diagrams on this link http://www.json.org/fatfree.html

There are various ways available to to convert JSON to javaobject and javaobject to JSON : One of them is http://wiki.fasterxml.com/JacksonInFiveMinutes

Answer 4

Adding detailed code here along with the imports .

If this helps.

import org.json.JSONException;
import org.json.JSONObject;

public class extractingJSON {

    public static void main(String[] args) throws JSONException {
        // TODO Auto-generated method stub

        String jsonStr = "{\"name\":\"SK\",\"arr\":{\"a\":\"1\",\"b\":\"2\"},\"arrArray\":[{\"a\":\"1\",\"b\":\"2\"}]}";
        JSONObject jsonObj = new JSONObject(jsonStr);
        String name = jsonObj.getString("name");
        System.out.println(name);

        String first = jsonObj.getJSONObject("arr").getString("a");
        System.out.println(first);

        first = jsonObj.getJSONArray("arrArray").getJSONObject(0).getString("a");
        System.out.println(first);



    }


}