Jackson: How to add custom property to the JSON without modifying the POJO

Question

I am developing a REST interface for my app using Jackson to serialize my POJO domain objects to JSON representation. I want to customize the serialization for some types to

Answer 1

I needed this ability as well; in my case, to support field expansion on REST services. I ended up developing a tiny framework to solve this problem, and it's open sourced on github. It's also available in the maven central repository.

It takes care of all the work. Simply wrap the POJO in a MorphedResult, and then add or remove properties at will. When serialized, the MorphedResult wrapper disappears and any 'changes' appear in the serialized JSON object.

MorphedResult result = new MorphedResult<>(pojo);
result.addExpansionData("my_extra_field", "some data");

See the github page for more details and examples. Be sure to register the libraries 'filter' with Jackson's object mapper like so:

ObjectMapper mapper = new ObjectMapper();
mapper.setFilters(new FilteredResultProvider());