How can I pass complex objects as arguments to a RESTful service?

I have successfully set up a quick test of creating a "REST-like" service that returns an object serialized to JSON, and that was quite easy and quick (based on this article).

But while returning JSON-ified objects was easy as peach, I have yet to see any examples dealing with input parameters that are not primitives. How can I pass in a complex object as an argument? I am using Apache CXF, but examples using other frameworks like Jackson are welcome too :)

Client side would probably be something like building a javascript object, pass it into JSON.stringify(complexObj), and pass that string as one of the parameters.

The service would probably look something like this

@Service("myService")
class RestService {
    @GET
    @Produces("application/json")
    @Path("/fooBar")
    public Result fooBar(@QueryParam("foo") double foo, @QueryParam("bar") double bar,
        @QueryParam("object") MyComplex object) throws WebServiceException {
    ...
    }
}

Sending serialized objects as parameters would probably quickly touch the 2KB URL-limit imposed by Internet Explorer. Would you recommend using POST in these cases, and would I need to change much in the function definitions?