Avoid duplicate registration of [RequestBody|ResponseBody]Advice

Prior to this commit, if a @ControllerAdvice bean implemented both
RequestBodyAdvice and ResponseBodyAdvice, it was registered twice in
RequestMappingHandlerAdapter, leading to duplicate application of the
same logic.

This commit ensures that such instances are only registered once.

Fixes gh-22638

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -107,6 +107,7 @@ import org.springframework.web.util.WebUtils;
  *
  * @author Rossen Stoyanchev
  * @author Juergen Hoeller
+ * @author Sam Brannen
  * @since 3.1
  * @see HandlerMethodArgumentResolver
  * @see HandlerMethodReturnValueHandler
@@ -612,16 +613,18 @@ public class RequestMappingHandlerAdapter extends AbstractHandlerMethodAdapter
 					logger.info("Detected @InitBinder methods in " + adviceBean);
 				}
 			}
-			if (RequestBodyAdvice.class.isAssignableFrom(beanType)) {
-				requestResponseBodyAdviceBeans.add(adviceBean);
-				if (logger.isInfoEnabled()) {
-					logger.info("Detected RequestBodyAdvice bean in " + adviceBean);
-				}
-			}
-			if (ResponseBodyAdvice.class.isAssignableFrom(beanType)) {
+
+			boolean isRequestBodyAdvice = RequestBodyAdvice.class.isAssignableFrom(beanType);
+			boolean isResponseBodyAdvice = ResponseBodyAdvice.class.isAssignableFrom(beanType);
+			if (isRequestBodyAdvice || isResponseBodyAdvice) {
 				requestResponseBodyAdviceBeans.add(adviceBean);
 				if (logger.isInfoEnabled()) {
-					logger.info("Detected ResponseBodyAdvice bean in " + adviceBean);
+					if (isRequestBodyAdvice) {
+						logger.info("Detected RequestBodyAdvice bean in " + adviceBean);
+					}
+					else {
+						logger.info("Detected ResponseBodyAdvice bean in " + adviceBean);
+					}
 				}
 			}
 		}