Question

Hi I am trying to use Json Simple to select the “cheese” entry, however I seem to be returning “null” when I try to select it. Would be excellent to have some advice on how to do this?`

Here is the Json sample:

String s="[\"coins\",{\"wallet\":{\"shoppinglist\":{\"cheese\":{\"ingrediants\":[\"milk\",{\"preservative1\":\"wax\"}]}}}}]";

and here is the code:

      System.out.println(s);
        System.out.println("=======decode=======");

      Object obj=JSONValue.parse(s);
      JSONArray array=(JSONArray)obj;
      System.out.println("======the 2nd element of array======");
      System.out.println(array.get(1));
      System.out.println();
      System.out.println("======the 1st element of array======");
      System.out.println(array.get(0));
      System.out.println();



      JSONObject obj2=(JSONObject)array.get(1);
      System.out.println("======field \"1\"==========");
      System.out.println(obj2.get("wallet"));  


      JSONObject obj3=(JSONObject) obj2.get("shoppinglist");
      System.out.println("======field \"2\"==========");
      System.out.println(obj3);  //This figure is returning null when I would like it to return the json object shopping list

It currently outputs:

     ["coins",{"wallet":{"shoppinglist":{"cheese":{"ingrediants":["milk",{"preservative1":"wax"}]}}}}]
    =======decode=======
    ======the 2nd element of array======
    {"wallet":{"shoppinglist":{"cheese":{"ingrediants":["milk",{"preservative1":"wax"}]}}}}

    ======the 1st element of array======
    coins

    ======field "1"==========
    {"shoppinglist":{"cheese":{"ingrediants":["milk",{"preservative1":"wax"}]}}}
    ======field "2"==========
    null

Answer 1

You’re skipping one step in the nesting. obj2 has the property “wallet”. “shoppinglist” is one level deeper.

To get the intended result, use this:

JSONObject wallet       = (JSONObject) obj2.get("wallet");
JSONObject shoppinglist = (JSONObject) wallet.get("shoppinglist");
System.out.println(shoppinglist);