Require type-level @controller annotation

Closes gh-22154

Author: rstoyanchev

spring-webflux/src/main/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerMapping.java

@@ -133,8 +133,7 @@ public void afterPropertiesSet() {
 	 */
 	@Override
 	protected boolean isHandler(Class<?> beanType) {
-		return (AnnotatedElementUtils.hasAnnotation(beanType, Controller.class) ||
-				AnnotatedElementUtils.hasAnnotation(beanType, RequestMapping.class));
+		return AnnotatedElementUtils.hasAnnotation(beanType, Controller.class);
 	}
 
 	/**

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.java

@@ -266,8 +266,7 @@ public RequestMappingInfo.BuilderConfiguration getBuilderConfiguration() {
 	 */
 	@Override
 	protected boolean isHandler(Class<?> beanType) {
-		return (AnnotatedElementUtils.hasAnnotation(beanType, Controller.class) ||
-				AnnotatedElementUtils.hasAnnotation(beanType, RequestMapping.class));
+		return AnnotatedElementUtils.hasAnnotation(beanType, Controller.class);
 	}
 
 	/**

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/HandlerMethodAnnotationDetectionTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2021 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -78,7 +78,7 @@ static Object[][] handlerTypes() {
 				// { ParameterizedSubclassDoesNotOverrideConcreteImplementationsFromGenericAbstractSuperclass.class, true }, // CGLIB proxy
 				// { ParameterizedSubclassDoesNotOverrideConcreteImplementationsFromGenericAbstractSuperclass.class, false },
 
-				{ InterfaceController.class, true }, // JDK dynamic proxy
+				// { InterfaceController.class, true }, // JDK dynamic proxy (gh-22154: no longer supported))
 				{ InterfaceController.class, false },
 
 				{ ParameterizedInterfaceController.class, false }, // no AOP
@@ -250,6 +250,7 @@ interface MappingInterface {
 	 * <p>JDK Dynamic proxy: All annotations must be on the interface.
 	 * <p>Without AOP: Annotations can be on interface methods except parameter annotations.
 	 */
+	@Controller
 	static class InterfaceController implements MappingInterface {
 
 		@Override
@@ -443,6 +444,7 @@ interface MappingGenericInterface<A, B, C> {
 	 * <p>All annotations can be on interface except parameter annotations.
 	 * <p>Cannot be used as JDK dynamic proxy since parameterized interface does not contain type information.
 	 */
+	@Controller
 	static class ParameterizedInterfaceController implements MappingGenericInterface<String, Date, Date> {
 
 		@Override

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/MvcUriComponentsBuilderTests.java

@@ -77,6 +77,7 @@
  * @author Rossen Stoyanchev
  * @author Sam Brannen
  */
+@SuppressWarnings("unused")
 public class MvcUriComponentsBuilderTests {
 
 	private final MockHttpServletRequest request = new MockHttpServletRequest();
@@ -455,7 +456,8 @@ public void fromControllerWithPrefix() {
 		this.request.setServerPort(9999);
 		this.request.setContextPath("/base");
 
-		assertThat(fromController(PersonsAddressesController.class).buildAndExpand("123").toString()).isEqualTo("https://example.org:9999/base/api/people/123/addresses");
+		assertThat(fromController(PersonsAddressesController.class).buildAndExpand("123").toString())
+				.isEqualTo("https://example.org:9999/base/api/people/123/addresses");
 	}
 
 	@Test
@@ -468,8 +470,12 @@ public void fromMethodWithPrefix() {
 		this.request.setServerPort(9999);
 		this.request.setContextPath("/base");
 
-		assertThat(fromMethodCall(on(PersonsAddressesController.class).getAddressesForCountry("DE"))
-				.buildAndExpand("123").toString()).isEqualTo("https://example.org:9999/base/api/people/123/addresses/DE");
+		String url = fromMethodCall(on(PersonsAddressesController.class)
+				.getAddressesForCountry("DE"))
+				.buildAndExpand("123")
+				.toString();
+
+		assertThat(url).isEqualTo("https://example.org:9999/base/api/people/123/addresses/DE");
 	}
 
 	private void initWebApplicationContext(Class<?> configClass) {
@@ -500,6 +506,7 @@ static class PersonControllerImpl implements PersonController {
 	}
 
 
+	@Controller
 	@RequestMapping("/people/{id}/addresses")
 	static class PersonsAddressesController {
 
@@ -509,6 +516,7 @@ HttpEntity<Void> getAddressesForCountry(@PathVariable String country) {
 		}
 	}
 
+	@Controller
 	@RequestMapping({"people"})
 	static class PathWithoutLeadingSlashController {
 

src/docs/asciidoc/web/webflux.adoc

@@ -1348,6 +1348,29 @@ directly to the response body versus view resolution and rendering with an HTML
 
 
 
+[[webflux-ann-requestmapping-proxying]]
+==== AOP Proxies
+[.small]#<<web.adoc#mvc-ann-requestmapping-proxying, Web MVC>>#
+
+In some cases, you may need to decorate a controller with an AOP proxy at runtime.
+One example is if you choose to have `@Transactional` annotations directly on the
+controller. When this is the case, for controllers specifically, we recommend
+using class-based proxying. This is automatically the case with such annotations
+directly on the controller.
+
+If the controller implements an interface, and needs AOP proxying, you may need to
+explicitly configure class-based proxying. For example, with `@EnableTransactionManagement`
+you can change to `@EnableTransactionManagement(proxyTargetClass = true)`, and with
+`<tx:annotation-driven/>` you can change to `<tx:annotation-driven proxy-target-class="true"/>`.
+
+NOTE: Keep in mind that as of 6.0, with interface proxying, Spring MVC no longer detects
+controllers based solely on a type-level `@RequestMapping` annotation on the interface.
+Please, enable class based proxying, or otherwise the interface must also have an
+`@Controller` annotation.
+
+
+
+
 [[webflux-ann-requestmapping]]
 === Request Mapping
 [.small]#<<web.adoc#mvc-ann-requestmapping, Web MVC>>#

src/docs/asciidoc/web/webmvc.adoc

@@ -1512,17 +1512,23 @@ directly to the response body versus view resolution and rendering with an HTML
 
 [[mvc-ann-requestmapping-proxying]]
 ==== AOP Proxies
+[.small]#<<web-reactive.adoc#webflux-ann-requestmapping-proxying, WebFlux>>#
 
 In some cases, you may need to decorate a controller with an AOP proxy at runtime.
 One example is if you choose to have `@Transactional` annotations directly on the
 controller. When this is the case, for controllers specifically, we recommend
-using class-based proxying. This is typically the default choice with controllers.
-However, if a controller must implement an interface that is not a Spring Context
-callback (such as `InitializingBean`, `*Aware`, and others), you may need to explicitly
-configure class-based proxying. For example, with `<tx:annotation-driven/>` you can
-change to `<tx:annotation-driven proxy-target-class="true"/>`, and with
-`@EnableTransactionManagement` you can change to
-`@EnableTransactionManagement(proxyTargetClass = true)`.
+using class-based proxying. This is automatically the case with such annotations
+directly on the controller.
+
+If the controller implements an interface, and needs AOP proxying, you may need to
+explicitly configure class-based proxying. For example, with `@EnableTransactionManagement`
+you can change to `@EnableTransactionManagement(proxyTargetClass = true)`, and with
+`<tx:annotation-driven/>` you can change to `<tx:annotation-driven proxy-target-class="true"/>`.
+
+NOTE: Keep in mind that as of 6.0, with interface proxying, Spring MVC no longer detects
+controllers based solely on a type-level `@RequestMapping` annotation on the interface.
+Please, enable class based proxying, or otherwise the interface must also have an
+`@Controller` annotation.