[java] JSONObject - How to get a value?

This may be helpful while searching keys present in nested objects and nested arrays. And this is a generic solution to all cases.

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

public class MyClass
{
    public static Object finalresult = null;
    public static void main(String args[]) throws JSONException
    {
        System.out.println(myfunction(myjsonstring,key));
    }

    public static Object myfunction(JSONObject x,String y) throws JSONException
    {
        JSONArray keys =  x.names();
        for(int i=0;i<keys.length();i++)
        {
            if(finalresult!=null)
            {
                return finalresult;                     //To kill the recursion
            }

            String current_key = keys.get(i).toString();

            if(current_key.equals(y))
            {
                finalresult=x.get(current_key);
                return finalresult;
            }

            if(x.get(current_key).getClass().getName().equals("org.json.JSONObject"))
            {
                myfunction((JSONObject) x.get(current_key),y);
            }
            else if(x.get(current_key).getClass().getName().equals("org.json.JSONArray"))
            {
                for(int j=0;j<((JSONArray) x.get(current_key)).length();j++)
                {
                    if(((JSONArray) x.get(current_key)).get(j).getClass().getName().equals("org.json.JSONObject"))
                    {
                        myfunction((JSONObject)((JSONArray) x.get(current_key)).get(j),y);
                    }
                }
            }
        }
        return null;
    }
}

Possibilities:

  1. "key":"value"
  2. "key":{Object}
  3. "key":[Array]

Logic :

  • I check whether the current key and search key are the same, if so I return the value of that key.
  • If it is an object, I send the value recursively to the same function.
  • If it is an array, I check whether it contains an object, if so I recursively pass the value to the same function.