MessageSource support for Spring MVC and WebFlux exceptions

See gh-28814

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

@@ -16,12 +16,17 @@
 
 package org.springframework.web.servlet.mvc.method.annotation;
 
+import java.util.Locale;
+
 import jakarta.servlet.http.HttpServletResponse;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.ConversionNotSupportedException;
 import org.springframework.beans.TypeMismatchException;
+import org.springframework.context.MessageSource;
+import org.springframework.context.MessageSourceAware;
+import org.springframework.context.i18n.LocaleContextHolder;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.HttpStatusCode;
@@ -64,7 +69,7 @@ import org.springframework.web.util.WebUtils;
  * @author Rossen Stoyanchev
  * @since 3.2
  */
-public abstract class ResponseEntityExceptionHandler {
+public abstract class ResponseEntityExceptionHandler implements MessageSourceAware {
 
 	/**
 	 * Log category to use when no mapped handler is found for a request.
@@ -84,6 +89,16 @@ public abstract class ResponseEntityExceptionHandler {
 	protected final Log logger = LogFactory.getLog(getClass());
 
 
+	@Nullable
+	private MessageSource messageSource;
+
+
+	@Override
+	public void setMessageSource(MessageSource messageSource) {
+		this.messageSource = messageSource;
+	}
+
+
 	/**
 	 * Handle all exceptions raised within Spring MVC handling of the request .
 	 * @param ex the exception to handle
@@ -504,12 +519,25 @@ public abstract class ResponseEntityExceptionHandler {
 		}
 
 		if (body == null && ex instanceof ErrorResponse errorResponse) {
-			body = errorResponse.getBody();
+			body = resolveDetailViaMessageSource(errorResponse);
 		}
 
 		return createResponseEntity(body, headers, statusCode, request);
 	}
 
+	private ProblemDetail resolveDetailViaMessageSource(ErrorResponse response) {
+		ProblemDetail body = response.getBody();
+		if (this.messageSource != null) {
+			Locale locale = LocaleContextHolder.getLocale();
+			Object[] arguments = response.getDetailMessageArguments(this.messageSource, locale);
+			String detail = this.messageSource.getMessage(response.getDetailMessageCode(), arguments, null, locale);
+			if (detail != null) {
+				body.setDetail(detail);
+			}
+		}
+		return body;
+	}
+
 	/**
 	 * Create the {@link ResponseEntity} to use from the given body, headers,
 	 * and statusCode. Subclasses can override this method to inspect and possibly

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

@@ -19,18 +19,22 @@ package org.springframework.web.servlet.mvc.method.annotation;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 
 import jakarta.servlet.ServletException;
 import org.junit.jupiter.api.Test;
 
 import org.springframework.beans.ConversionNotSupportedException;
 import org.springframework.beans.TypeMismatchException;
+import org.springframework.context.i18n.LocaleContextHolder;
+import org.springframework.context.support.StaticMessageSource;
 import org.springframework.core.MethodParameter;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.HttpStatusCode;
 import org.springframework.http.MediaType;
+import org.springframework.http.ProblemDetail;
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.http.converter.HttpMessageNotWritableException;
@@ -106,7 +110,7 @@ public class ResponseEntityExceptionHandlerTests {
 	}
 
 	@Test
-	public void handleHttpMediaTypeNotSupported() {
+	public void httpMediaTypeNotSupported() {
 		ResponseEntity<Object> entity = testException(new HttpMediaTypeNotSupportedException(
 				MediaType.APPLICATION_JSON, List.of(MediaType.APPLICATION_ATOM_XML, MediaType.APPLICATION_XML)));
 
@@ -152,6 +156,32 @@ public class ResponseEntityExceptionHandlerTests {
 		testException(new ServletRequestBindingException("message"));
 	}
 
+	@Test
+	public void errorResponseProblemDetailViaMessageSource() {
+
+		Locale locale = Locale.UK;
+		LocaleContextHolder.setLocale(locale);
+
+		try {
+			StaticMessageSource messageSource = new StaticMessageSource();
+			messageSource.addMessage(
+					"problemDetail." + HttpMediaTypeNotSupportedException.class.getName(), locale,
+					"Content-Type {0} not supported. Supported: {1}");
+
+			this.exceptionHandler.setMessageSource(messageSource);
+
+			ResponseEntity<?> entity = testException(new HttpMediaTypeNotSupportedException(
+					MediaType.APPLICATION_JSON, List.of(MediaType.APPLICATION_ATOM_XML, MediaType.APPLICATION_XML)));
+
+			ProblemDetail body = (ProblemDetail) entity.getBody();
+			assertThat(body.getDetail()).isEqualTo(
+					"Content-Type application/json not supported. Supported: [application/atom+xml, application/xml]");
+		}
+		finally {
+			LocaleContextHolder.resetLocaleContext();
+		}
+	}
+
 	@Test
 	public void conversionNotSupported() {
 		testException(new ConversionNotSupportedException(new Object(), Object.class, null));

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/support/DefaultHandlerExceptionResolverTests.java

@@ -17,6 +17,7 @@
 package org.springframework.web.servlet.mvc.support;
 
 import java.lang.reflect.Method;
+import java.util.Arrays;
 import java.util.Collections;
 
 import org.junit.jupiter.api.BeforeEach;
@@ -71,7 +72,7 @@ public class DefaultHandlerExceptionResolverTests {
 	@Test
 	public void handleHttpRequestMethodNotSupported() {
 		HttpRequestMethodNotSupportedException ex =
-				new HttpRequestMethodNotSupportedException("GET", new String[]{"POST", "PUT"});
+				new HttpRequestMethodNotSupportedException("GET", Arrays.asList("POST", "PUT"));
 		ModelAndView mav = exceptionResolver.resolveException(request, response, null, ex);
 		assertThat(mav).as("No ModelAndView returned").isNotNull();
 		assertThat(mav.isEmpty()).as("No Empty ModelAndView returned").isTrue();