java - Specify message converters for single Spring Controller

Question

I'm writing a postback handler library for a service that has some odd JSON mapping practices. I can very easily configure a custom Jackson ObjectMapper to handle the mapping, but if I register a Spring MVC message converter with that mapper, it applies the mapping (which is incorrect for the rest of the JSON I'm dealing with) to all incoming requests.

There are a handful of manual approaches I can apply to hand-decode these messages, but it would be much cleaner to have the Spring type-conversion service handle it in the request pipeline.

Is there a feasible way to attach a custom message converter to a specific controller, handler method, or mapping string/template/prefix?

Answer 1

I had a similar situation - I wanted to create custom @ResponseBody equivalent that would allow me to configure certain aspects of JSON serialization (in my example, I wanted JSON values optionally html encoded). I ended up creating custom @JsonResponseBodyannotation which would cause spring mvc to use differently configured Jackson message converter for methods annotated with it.

I had to extend Spring's AbstractMessageConverterMethodProcessorto register custom handling for my custom annotation and then I needed to register my CustomAbstractMessageConverterMethodProcessor with spring framework by adding it to RequestMappingHandlerAdapter's list of handlers. This was also tricky, because if you use xml config you have to do it via BeanPostProcessor.

At the time I was attempting this (year ago, Spring 3.1), I didn't find any easier way.