Expose return-value-handlers in mvc namespace

Mirroring the MvcConfigurer#addCustomReturnValueHandlers callback which
allows for providing a list of HandlerMethodReturnValueHandler types

org.springframework.web.servlet/src/test/java/org/springframework/web/servlet/config/AnnotationDrivenBeanDefinitionParserTests.java

@@ -37,6 +37,7 @@ import org.springframework.web.bind.support.WebDataBinderFactory;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.context.support.GenericWebApplicationContext;
 import org.springframework.web.method.support.HandlerMethodArgumentResolver;
+import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
 import org.springframework.web.method.support.ModelAndViewContainer;
 import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter;
 import org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver;
@@ -96,6 +97,20 @@ public class AnnotationDrivenBeanDefinitionParserTests {
 		assertTrue(resolvers.get(1) instanceof TestHandlerMethodArgumentResolver);
 	}
 
+	@SuppressWarnings("unchecked")
+	@Test
+	public void testReturnValueHandlers() {
+		loadBeanDefinitions("mvc-config-return-value-handlers.xml");
+		RequestMappingHandlerAdapter adapter = appContext.getBean(RequestMappingHandlerAdapter.class);
+		assertNotNull(adapter);
+		Object value = new DirectFieldAccessor(adapter).getPropertyValue("customReturnValueHandlers");
+		assertNotNull(value);
+		assertTrue(value instanceof List);
+		List<HandlerMethodReturnValueHandler> handlers = (List<HandlerMethodReturnValueHandler>) value;
+		assertEquals(1, handlers.size());
+		assertEquals(TestHandlerMethodReturnValueHandler.class, handlers.get(0).getClass());
+	}
+
 	private void loadBeanDefinitions(String fileName) {
 		XmlBeanDefinitionReader reader = new XmlBeanDefinitionReader(appContext);
 		reader.loadBeanDefinitions(new ClassPathResource(fileName,
@@ -141,6 +156,19 @@ class TestHandlerMethodArgumentResolver implements HandlerMethodArgumentResolver
 	}
 }
 
+class TestHandlerMethodReturnValueHandler implements HandlerMethodReturnValueHandler {
+
+	public boolean supportsReturnType(MethodParameter returnType) {
+		return false;
+	}
+
+	public void handleReturnValue(Object returnValue,
+			MethodParameter returnType, ModelAndViewContainer mavContainer,
+			NativeWebRequest webRequest) throws Exception {
+	}
+	
+}
+
 class TestMessageCodesResolver implements MessageCodesResolver {
 
 	public String[] resolveMessageCodes(String errorCode, String objectName) {

org.springframework.web.servlet/src/test/resources/org/springframework/web/servlet/config/mvc-config-return-value-handlers.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+    xmlns:mvc="http://www.springframework.org/schema/mvc"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
+		http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd">
+
+	<mvc:annotation-driven>
+		<mvc:return-value-handlers>
+			<bean class="org.springframework.web.servlet.config.TestHandlerMethodReturnValueHandler"/>
+		</mvc:return-value-handlers>
+	</mvc:annotation-driven>
+
+</beans>