Delegating HTTP request handling from a Spring MVC Controller to Jersey 2 - spring-mvc

Question

I'm trying to plug my set of RESTful endpoints (which rely on Jersey 2 JAX-RS implementation) into a 3rd party Spring MVC web application running on top of Tomcat 9.
I'm not allowed to modify web.xml, nor is my plug-in available when the container starts, so annotation-based configuration is not an option, either. This means I can't deploy Jersey's ServletContainer directly.
What I am allowed is plugging into Spring MVC, namely
creating a custom partial Spring application context and
implementing a custom Controller, so I have written this naïve implementation which is actually close to the standard ServletWrappingController:
package com.example
import org.glassfish.jersey.server.ResourceConfig
import org.glassfish.jersey.servlet.ServletContainer
import org.springframework.web.servlet.ModelAndView
import org.springframework.web.servlet.mvc.AbstractController
import java.io.IOException
import java.util.Collections
import java.util.Enumeration
import javax.servlet.ServletConfig
import javax.servlet.ServletContext
import javax.servlet.http.HttpServletRequest
import javax.servlet.http.HttpServletResponse
class JerseyServletInitializer(servletContext: ServletContext,
componentClasses: List<Class<*>>,
components: List<Any>): AbstractController() {
private val servletContainer: ServletContainer
init {
val resourceConfig = ResourceConfig()
.apply {
// Register org.glassfish.jersey.media.multipart.MultiPartFeature
componentClasses.forEach { clazz ->
register(clazz)
}
// Register REST endpoints
components.forEach { component ->
register(component)
}
}
// Provide a dummy ServletConfig
val servletConfig = object : ServletConfig {
override fun getInitParameter(name: String): String? = null
override fun getInitParameterNames(): Enumeration<String> = emptyList<String>().let {
Collections.enumeration(it)
}
override fun getServletName(): String = ServletContainer::class.java.name
override fun getServletContext(): ServletContext = servletContext
}
// Create and initialize Jersey's ServletContainer
servletContainer = ServletContainer(resourceConfig).apply {
init(servletConfig)
}
setSupportedMethods("GET", "POST", "PUT", "OPTIONS")
}
#Throws(IOException::class)
override fun handleRequestInternal(request: HttpServletRequest,
response: HttpServletResponse): ModelAndView? {
// Delegate all HTTP requests to Jersey
servletContainer.service(request, response)
return null
}
}
The above works fine with the only exception of file upload scenario (i. e. HTTP POST with Content-Type: multipart/form-data).
Spring detects such requests and converts a regular HttpServletRequest into a MultipartHttpServletRequest, reading out and exhausting its input stream (mark()/reset() are not supported). The web application has a custom MultipartResolver which I can't affect in any way:
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"/>
This means Jersey receives a multipart HTTP POST with an empty request body, throws a MIMEParsingException and responds with HTTP 400 Bad Request.
As far as I understand, multipart resolution can only be disabled globally, and not on a per-controller basis (1, 2, 3).
Questions:
What is the best way to work the MultipartResolver around, so that Jersey receives an non-modified request?
Alternatively, can you recommend an API to re-construct the request body (i. e. do the opposite of what MultipartResolver does and feed the new HttpServletRequest to Jersey)? This can, of course, be done by hand, but I'd rather rely on the existing libraries.