Get data from multi level json string

Question

I am getting some data in response to my code which is a JSON string as:

HTTPResponse res = {"id":2048,"extension_attributes":{"stock_item":{"stock_id":1}}}

Now to retrieve data, I've done

Map<String, Object> results = (Map<String, Object>) JSON.deserializeUntyped(res.getBody());
Object attr = results.get('extension_attributes');

Here attr is again containing 'stock_item' which finally contains 'stock_id'. Though I am unable to get this by any way from this object. I hope someone would have solution for this.

Answer 1

Each object in your JSON becomes a Map<String, Object> when you deserialize untyped. You just need to cast it as such to be able to use it.

Map<String, Object> results = (Map<String, Object>) JSON.deserializeUntyped(res.getBody());
Map<String, Object> attr = (Map<String, Object>)results.get('extension_attributes');
System.debug(attr.get('stock_item'));

Continue as needed until you can extract the data you want.

At a point, though, it'll make more sense to use an Apex class to deserialize so you don't need to cast things ad nauseum.