Parsing a long value leads to different value as double

[dstrasse]

Hi,
my REST response contains something like

"myId":7000000000000125407
The JSON is a little bit more complex so a Map is used as the basic data type.
Unfortunately, the value for my given ID will be a different one after parsing since Gson casts to double directly which leads to the following value in my map:

(double)7000000000000125407l -> 7.0000000000001249E18

Unfortunately, the JSON is supplied by a 3rd party system and cannot be modified, so I cannot add quotes. A way to enforce Strings for defined types would be great.

[pakopa]

When no data type is specified, gson reads al numbers as doubles (see: com.google.gson.internal.bind.ObjectTypeAdapter:78-79) and there is no way to plug a custom ObjectTypeAdapter since it is designed taht way (see: com.google.gson.internal.bind.ObjectTypeAdapter:198-208)

I think there should be a way to define a custom ObjectTypeAdapter

In the meantime I managed to come with the following workaround.

1. Define a custom empty class that will be used as a flag for deserialization.
2. Copy the implementation of ObjectTypeAdpater and modify the deserialization. (I went for bigdecimals)
3. Register a typeAdapterFactory that instantiates your ObjectTypeAdapter for the flag class in the GsonBuilder creating your gson object.
4. Deserialize with Object o = gson.fromJson(reader, YourFlagClass.class) (thanks type erasure)

I had to twist the API way too much for something that should be easily achievable.

[eamonnmcmanus]

Fixed by #1290.