Avoid repeated calls of WebFlux and MVC registrations' getters

See gh-23999

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/reactive/WebFluxAutoConfiguration.java

@@ -248,18 +248,22 @@ public class WebFluxAutoConfiguration {
 
 		@Override
 		protected RequestMappingHandlerAdapter createRequestMappingHandlerAdapter() {
-			if (this.webFluxRegistrations != null
-					&& this.webFluxRegistrations.getRequestMappingHandlerAdapter() != null) {
-				return this.webFluxRegistrations.getRequestMappingHandlerAdapter();
+			if (this.webFluxRegistrations != null) {
+				RequestMappingHandlerAdapter adapter = this.webFluxRegistrations.getRequestMappingHandlerAdapter();
+				if (adapter != null) {
+					return adapter;
+				}
 			}
 			return super.createRequestMappingHandlerAdapter();
 		}
 
 		@Override
 		protected RequestMappingHandlerMapping createRequestMappingHandlerMapping() {
-			if (this.webFluxRegistrations != null
-					&& this.webFluxRegistrations.getRequestMappingHandlerMapping() != null) {
-				return this.webFluxRegistrations.getRequestMappingHandlerMapping();
+			if (this.webFluxRegistrations != null) {
+				RequestMappingHandlerMapping mapping = this.webFluxRegistrations.getRequestMappingHandlerMapping();
+				if (mapping != null) {
+					return mapping;
+				}
 			}
 			return super.createRequestMappingHandlerMapping();
 		}

spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfiguration.java

@@ -402,8 +402,11 @@ public class WebMvcAutoConfiguration {
 
 		@Override
 		protected RequestMappingHandlerAdapter createRequestMappingHandlerAdapter() {
-			if (this.mvcRegistrations != null && this.mvcRegistrations.getRequestMappingHandlerAdapter() != null) {
-				return this.mvcRegistrations.getRequestMappingHandlerAdapter();
+			if (this.mvcRegistrations != null) {
+				RequestMappingHandlerAdapter adapter = this.mvcRegistrations.getRequestMappingHandlerAdapter();
+				if (adapter != null) {
+					return adapter;
+				}
 			}
 			return super.createRequestMappingHandlerAdapter();
 		}
@@ -470,8 +473,11 @@ public class WebMvcAutoConfiguration {
 
 		@Override
 		protected RequestMappingHandlerMapping createRequestMappingHandlerMapping() {
-			if (this.mvcRegistrations != null && this.mvcRegistrations.getRequestMappingHandlerMapping() != null) {
-				return this.mvcRegistrations.getRequestMappingHandlerMapping();
+			if (this.mvcRegistrations != null) {
+				RequestMappingHandlerMapping mapping = this.mvcRegistrations.getRequestMappingHandlerMapping();
+				if (mapping != null) {
+					return mapping;
+				}
 			}
 			return super.createRequestMappingHandlerMapping();
 		}
@@ -489,8 +495,11 @@ public class WebMvcAutoConfiguration {
 
 		@Override
 		protected ExceptionHandlerExceptionResolver createExceptionHandlerExceptionResolver() {
-			if (this.mvcRegistrations != null && this.mvcRegistrations.getExceptionHandlerExceptionResolver() != null) {
-				return this.mvcRegistrations.getExceptionHandlerExceptionResolver();
+			if (this.mvcRegistrations != null) {
+				ExceptionHandlerExceptionResolver resolver = this.mvcRegistrations.getExceptionHandlerExceptionResolver();
+				if (resolver != null) {
+					return resolver;
+				}
 			}
 			return super.createExceptionHandlerExceptionResolver();
 		}