Merge pull request #40874 from rohitp-a

* gh-40874:
  Polish "Make it easier to override RequestToViewNameTranslator bean"
  Make it easier to override RequestToViewNameTranslator bean

Closes gh-40874

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

@@ -95,6 +95,7 @@ import org.springframework.web.servlet.DispatcherServlet;
 import org.springframework.web.servlet.FlashMapManager;
 import org.springframework.web.servlet.HandlerExceptionResolver;
 import org.springframework.web.servlet.LocaleResolver;
+import org.springframework.web.servlet.RequestToViewNameTranslator;
 import org.springframework.web.servlet.View;
 import org.springframework.web.servlet.ViewResolver;
 import org.springframework.web.servlet.config.annotation.AsyncSupportConfigurer;
@@ -469,6 +470,13 @@ public class WebMvcAutoConfiguration {
 			return super.flashMapManager();
 		}
 
+		@Override
+		@Bean
+		@ConditionalOnMissingBean(name = DispatcherServlet.REQUEST_TO_VIEW_NAME_TRANSLATOR_BEAN_NAME)
+		public RequestToViewNameTranslator viewNameTranslator() {
+			return super.viewNameTranslator();
+		}
+
 		private Resource getIndexHtmlResource() {
 			for (String location : this.resourceProperties.getStaticLocations()) {
 				Resource indexHtml = getIndexHtmlResource(location);

spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/servlet/WebMvcAutoConfigurationTests.java

@@ -102,6 +102,7 @@ import org.springframework.web.servlet.HandlerAdapter;
 import org.springframework.web.servlet.HandlerExceptionResolver;
 import org.springframework.web.servlet.HandlerMapping;
 import org.springframework.web.servlet.LocaleResolver;
+import org.springframework.web.servlet.RequestToViewNameTranslator;
 import org.springframework.web.servlet.View;
 import org.springframework.web.servlet.ViewResolver;
 import org.springframework.web.servlet.config.annotation.AsyncSupportConfigurer;
@@ -136,6 +137,7 @@ import org.springframework.web.servlet.support.AbstractFlashMapManager;
 import org.springframework.web.servlet.support.SessionFlashMapManager;
 import org.springframework.web.servlet.view.AbstractView;
 import org.springframework.web.servlet.view.ContentNegotiatingViewResolver;
+import org.springframework.web.servlet.view.DefaultRequestToViewNameTranslator;
 import org.springframework.web.util.UrlPathHelper;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -404,6 +406,26 @@ class WebMvcAutoConfigurationTests {
 			});
 	}
 
+	@Test
+	void customViewNameTranslatorWithMatchingNameReplacesDefaultViewNameTranslator() {
+		this.contextRunner.withBean("viewNameTranslator", CustomViewNameTranslator.class, CustomViewNameTranslator::new)
+			.run((context) -> {
+				assertThat(context).hasSingleBean(RequestToViewNameTranslator.class);
+				assertThat(context.getBean("viewNameTranslator")).isInstanceOf(CustomViewNameTranslator.class);
+			});
+	}
+
+	@Test
+	void customViewNameTranslatorWithDifferentNameDoesNotReplaceDefaultViewNameTranslator() {
+		this.contextRunner
+			.withBean("customViewNameTranslator", CustomViewNameTranslator.class, CustomViewNameTranslator::new)
+			.run((context) -> {
+				assertThat(context.getBean("customViewNameTranslator")).isInstanceOf(CustomViewNameTranslator.class);
+				assertThat(context.getBean("viewNameTranslator"))
+					.isInstanceOf(DefaultRequestToViewNameTranslator.class);
+			});
+	}
+
 	@Test
 	void defaultDateFormat() {
 		this.contextRunner.run((context) -> {
@@ -1458,6 +1480,15 @@ class WebMvcAutoConfigurationTests {
 
 	}
 
+	static class CustomViewNameTranslator implements RequestToViewNameTranslator {
+
+		@Override
+		public String getViewName(HttpServletRequest requestAttributes) {
+			return null;
+		}
+
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	static class ResourceHandlersWithChildAndParentContextConfiguration {