根据路径或参数在2个不同的MarshallingHttpMessageConverter实例之间进行选择

Question

Scenario :

In a Spring MVC controller (within a SpringBoot 1.2.5 microservice) I have an endpoint which returns a JAXBElement<?> which is marshalled to XML via a configured MarshallingHttpMessageConverter bean. This works perfectly fine and currently does not perform validation against any schemas - it just spits out an XML representation of a domain object.

Problem

What I would like to be able to do on a per-request basis is specify whether validation should be performed during marshalling, so I can report any problems to the client - but still have the option to simply marshall with no validation. Modifying the underlying Jaxb2Marshaller to do the validation is no problem, I just set the appropriate schema with setSchema and it works.

Given that MarshallingHttpMessageConverter works with a single marshaller instance that is either configured to validate or not, and content negotiation is based on the accept header, how can I modify the setup to facilitate selective validation per request (based on a query parameter or path) - preferably whilst still relying on Spring's content-negotiation magic to do the 'hard work'?

Answer 1

As a (hopefully temporary) workaround, I have bypassed the auto content-negotiation provided by MarshallingHttpMessageConverter , instead creating two separate Jaxb2Marshaller beans, one which validates and one which doesn't, and using them directly within the controller method to marshall to a StringResult , then returning that as a HttpEntity<String> . More manual steps required, but it works and I can easily switch between validating / not validating based on a request parameter (or whatever).

I won't accept this answer just in case anyone else comes up with a cleaner solution.