Deserialize JSON Root Array

Question

I'm having so trouble deserializing a JSON stream that contains an array as the root:

[
    {
        "object": {
                     "property1":"000000",
                     "property2":"000000"
                  }
    },
    {
        "object": {
                     "property1":"000000",
                     "property2":"000000"
                  }
    }
]

I tried using JSON.deserializeUntyped and assigning to a Map, but I keep getting a "invalid conversion runtime type LIST to MAP". This method worked fine when I was dealing with single JSON objects, but loading multiples into an array trips this error. Should I be using a different type for deserialization?

Answer 1

You have to cast it into a List<Object>, and for each element in the list, you can access the values as a Map<Object,Object>.

Answer 2

As well as containing the extra commas, the JSON you show is an array of objects. You have to type convert it in two steps:

String s = '[{"object": {"property1":"000000","property2":"000000"}},'
        + '{"object": {"property1":"000000","property2":"000000"}}]';

List<Object> l = (List<Object>) JSON.deserializeUntyped (s);
for (Object o : l) {
    Map<String, Object> m = (Map<String, Object>) o;
    System.debug('>>> m=' + m);
}