Gson to HashMap

Question

Is there a way to convert a String containing json to a HashMap, where every key is a json-key and the value is the value of the json-key? The json has no nested values. I a

Answer 1

Use TypeToken, as per the GSON FAQ:

Gson gson = new Gson();
Type stringStringMap = new TypeToken<Map<String, String>>(){}.getType();
Map<String,String> map = gson.fromJson(json, stringStringMap);

No casting. No unnecessary object creation.

Answer 2

I like:

private static class MyMap extends HashMap<String,String> {};
...
MyMap map = gson.fromJson(json, MyMap.class);

Answer 3

If I use the TypeToken solution with a Map<Enum, Object> I get "duplicate key: null".

The best solution for me is:

String json = "{\"id\":3,\"location\":\"NewYork\"}";
Gson gson = new Gson();
Map<String, Object> map = new HashMap<String, Object>();
map = (Map<String, Object>)gson.fromJson(json, map.getClass());

Result:

{id=3.0, location=NewYork}