Merge path extension related deprecation changes

Closes gh-24179

spring-test/src/main/java/org/springframework/test/web/servlet/setup/StandaloneMockMvcBuilder.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -310,7 +310,11 @@ public class StandaloneMockMvcBuilder extends AbstractMockMvcBuilder<StandaloneM
 	 * Whether to use suffix pattern match (".*") when matching patterns to
 	 * requests. If enabled a method mapped to "/users" also matches to "/users.*".
 	 * <p>The default value is {@code true}.
+	 * @deprecated as of 5.2.4. See class-level note in
+	 * {@link RequestMappingHandlerMapping} on the deprecation of path extension
+	 * config options.
 	 */
+	@Deprecated
 	public StandaloneMockMvcBuilder setUseSuffixPatternMatch(boolean useSuffixPatternMatch) {
 		this.useSuffixPatternMatch = useSuffixPatternMatch;
 		return this;
@@ -442,6 +446,7 @@ public class StandaloneMockMvcBuilder extends AbstractMockMvcBuilder<StandaloneM
 	/** Using the MVC Java configuration as the starting point for the "standalone" setup. */
 	private class StandaloneConfiguration extends WebMvcConfigurationSupport {
 
+		@SuppressWarnings("deprecation")
 		public RequestMappingHandlerMapping getHandlerMapping(
 				FormattingConversionService mvcConversionService,
 				ResourceUrlProvider mvcResourceUrlProvider) {

spring-web/src/main/java/org/springframework/web/accept/ContentNegotiationManager.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -20,13 +20,17 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.LinkedHashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
+import java.util.function.Function;
 
 import org.springframework.http.MediaType;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
 import org.springframework.web.HttpMediaTypeNotAcceptableException;
 import org.springframework.web.context.request.NativeWebRequest;
 
@@ -132,11 +136,7 @@ public class ContentNegotiationManager implements ContentNegotiationStrategy, Me
 
 	@Override
 	public List<String> resolveFileExtensions(MediaType mediaType) {
-		Set<String> result = new LinkedHashSet<>();
+		return doResolveExtensions(resolver -> resolver.resolveFileExtensions(mediaType));
-		for (MediaTypeFileExtensionResolver resolver : this.resolvers) {
-			result.addAll(resolver.resolveFileExtensions(mediaType));
-		}
-		return new ArrayList<>(result);
 	}
 
 	/**
@@ -152,11 +152,44 @@ public class ContentNegotiationManager implements ContentNegotiationStrategy, Me
 	 */
 	@Override
 	public List<String> getAllFileExtensions() {
-		Set<String> result = new LinkedHashSet<>();
+		return doResolveExtensions(MediaTypeFileExtensionResolver::getAllFileExtensions);
+	}
+
+	private List<String> doResolveExtensions(Function<MediaTypeFileExtensionResolver, List<String>> extractor) {
+		List<String> result = null;
 		for (MediaTypeFileExtensionResolver resolver : this.resolvers) {
-			result.addAll(resolver.getAllFileExtensions());
+			List<String> extensions = extractor.apply(resolver);
+			if (CollectionUtils.isEmpty(extensions)) {
+				continue;
+			}
+			result = (result != null ? result : new ArrayList<>(4));
+			for (String extension : extensions) {
+				if (!result.contains(extension)) {
+					result.add(extension);
+				}
+			}
 		}
-		return new ArrayList<>(result);
+		return (result != null ? result : Collections.emptyList());
+	}
+
+	/**
+	 * Return all registered lookup key to media type mappings by iterating
+	 * {@link MediaTypeFileExtensionResolver}s.
+	 * @since 5.2.4
+	 */
+	public Map<String, MediaType> getMediaTypeMappings() {
+		Map<String, MediaType> result = null;
+		for (MediaTypeFileExtensionResolver resolver : this.resolvers) {
+			if (resolver instanceof MappingMediaTypeFileExtensionResolver) {
+				Map<String, MediaType> map = ((MappingMediaTypeFileExtensionResolver) resolver).getMediaTypes();
+				if (CollectionUtils.isEmpty(map)) {
+					continue;
+				}
+				result = (result != null ? result : new HashMap<>(4));
+				result.putAll(map);
+			}
+		}
+		return (result != null ? result : Collections.emptyMap());
 	}
 
 }

spring-web/src/main/java/org/springframework/web/accept/ContentNegotiationManagerFactoryBean.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -81,15 +81,18 @@ import org.springframework.web.context.ServletContextAware;
  * </tr>
  * </table>
  *
- * <p>As of 5.0 you can set the exact strategies to use via
+ * <p>Alternatively you can avoid use of the above convenience builder
+ * methods and set the exact strategies to use via
  * {@link #setStrategies(List)}.
  *
- * <p><strong>Note:</strong> if you must use URL-based content type resolution,
+ * <p><strong>Note:</strong> As of 5.2.4,
- * the use of a query parameter is simpler and preferable to the use of a path
+ * {@link #setFavorPathExtension(boolean) favorPathExtension} and
- * extension since the latter can cause issues with URI variables, path
+ * {@link #setIgnoreUnknownPathExtensions(boolean) ignoreUnknownPathExtensions}
- * parameters, and URI decoding. Consider setting {@link #setFavorPathExtension}
+ * are deprecated in order to discourage use of path extensions for content
- * to {@literal false} or otherwise set the strategies to use explicitly via
+ * negotiation as well as for request mapping (with similar deprecations in
- * {@link #setStrategies(List)}.
+ * {@link org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping
+ * RequestMappingHandlerMapping}). For further context, please read issue
+ * <a href="https://github.com/spring-projects/spring-framework/issues/24179">#24719</a>.
  *
  * @author Rossen Stoyanchev
  * @author Brian Clozel
@@ -145,52 +148,61 @@ public class ContentNegotiationManagerFactoryBean
 	 * <p>By default this is set to {@code true} in which case a request
 	 * for {@code /hotels.pdf} will be interpreted as a request for
 	 * {@code "application/pdf"} regardless of the 'Accept' header.
+	 * @deprecated as of 5.2.4. See class-level note on the deprecation of path
+	 * extension config options.
 	 */
+	@Deprecated
 	public void setFavorPathExtension(boolean favorPathExtension) {
 		this.favorPathExtension = favorPathExtension;
 	}
 
 	/**
-	 * Add a mapping from a key, extracted from a path extension or a query
+	 * Add a mapping from a key to a MediaType where the key are normalized to
-	 * parameter, to a MediaType. This is required in order for the parameter
+	 * lowercase and may have been extracted from a path extension, a filename
-	 * strategy to work. Any extensions explicitly registered here are also
+	 * extension, or passed as a query parameter.
-	 * whitelisted for the purpose of Reflected File Download attack detection
+	 * <p>The {@link #setFavorParameter(boolean) parameter strategy} requires
-	 * (see Spring Framework reference documentation for more details on RFD
+	 * such mappings in order to work while the {@link #setFavorPathExtension(boolean)
-	 * attack protection).
+	 * path extension strategy} can fall back on lookups via
-	 * <p>The path extension strategy will also try to use
 	 * {@link ServletContext#getMimeType} and
-	 * {@link org.springframework.http.MediaTypeFactory} to resolve path extensions.
+	 * {@link org.springframework.http.MediaTypeFactory}.
+	 * <p><strong>Note:</strong> Mappings registered here may be accessed via
+	 * {@link ContentNegotiationManager#getMediaTypeMappings()} and may be used
+	 * not only in the parameter and path extension strategies. For example,
+	 * with the Spring MVC config, e.g. {@code @EnableWebMvc} or
+	 * {@code <mvc:annotation-driven>}, the media type mappings are also plugged
+	 * in to:
+	 * <ul>
+	 * <li>Determine the media type of static resources served with
+	 * {@code ResourceHttpRequestHandler}.
+	 * <li>Determine the media type of views rendered with
+	 * {@code ContentNegotiatingViewResolver}.
+	 * <li>Whitelist extensions for RFD attack detection (check the Spring
+	 * Framework reference docs for details).
+	 * </ul>
 	 * @param mediaTypes media type mappings
 	 * @see #addMediaType(String, MediaType)
 	 * @see #addMediaTypes(Map)
 	 */
 	public void setMediaTypes(Properties mediaTypes) {
 		if (!CollectionUtils.isEmpty(mediaTypes)) {
-			mediaTypes.forEach((key, value) -> {
+			mediaTypes.forEach((key, value) ->
-				String extension = ((String) key).toLowerCase(Locale.ENGLISH);
+					addMediaType((String) key, MediaType.valueOf((String) value)));
-				MediaType mediaType = MediaType.valueOf((String) value);
-				this.mediaTypes.put(extension, mediaType);
-			});
 		}
 	}
 
 	/**
-	 * An alternative to {@link #setMediaTypes} for use in Java code.
+	 * An alternative to {@link #setMediaTypes} for programmatic registrations.
-	 * @see #setMediaTypes
-	 * @see #addMediaTypes
 	 */
-	public void addMediaType(String fileExtension, MediaType mediaType) {
+	public void addMediaType(String key, MediaType mediaType) {
-		this.mediaTypes.put(fileExtension, mediaType);
+		this.mediaTypes.put(key.toLowerCase(Locale.ENGLISH), mediaType);
 	}
 
 	/**
-	 * An alternative to {@link #setMediaTypes} for use in Java code.
+	 * An alternative to {@link #setMediaTypes} for programmatic registrations.
-	 * @see #setMediaTypes
-	 * @see #addMediaType
 	 */
 	public void addMediaTypes(@Nullable Map<String, MediaType> mediaTypes) {
 		if (mediaTypes != null) {
-			this.mediaTypes.putAll(mediaTypes);
+			mediaTypes.forEach(this::addMediaType);
 		}
 	}
 
@@ -199,7 +211,10 @@ public class ContentNegotiationManagerFactoryBean
 	 * to any media type. Setting this to {@code false} will result in an
 	 * {@code HttpMediaTypeNotAcceptableException} if there is no match.
 	 * <p>By default this is set to {@code true}.
+	 * @deprecated as of 5.2.4. See class-level note on the deprecation of path
+	 * extension config options.
 	 */
+	@Deprecated
 	public void setIgnoreUnknownPathExtensions(boolean ignore) {
 		this.ignoreUnknownPathExtensions = ignore;
 	}
@@ -303,9 +318,10 @@ public class ContentNegotiationManagerFactoryBean
 	}
 
 	/**
-	 * Actually build the {@link ContentNegotiationManager}.
+	 * Create and initialize a {@link ContentNegotiationManager} instance.
 	 * @since 5.0
 	 */
+	@SuppressWarnings("deprecation")
 	public ContentNegotiationManager build() {
 		List<ContentNegotiationStrategy> strategies = new ArrayList<>();
 
@@ -327,7 +343,6 @@ public class ContentNegotiationManagerFactoryBean
 				}
 				strategies.add(strategy);
 			}
-
 			if (this.favorParameter) {
 				ParameterContentNegotiationStrategy strategy = new ParameterContentNegotiationStrategy(this.mediaTypes);
 				strategy.setParameterName(this.parameterName);
@@ -339,17 +354,24 @@ public class ContentNegotiationManagerFactoryBean
 				}
 				strategies.add(strategy);
 			}
-
 			if (!this.ignoreAcceptHeader) {
 				strategies.add(new HeaderContentNegotiationStrategy());
 			}
-
 			if (this.defaultNegotiationStrategy != null) {
 				strategies.add(this.defaultNegotiationStrategy);
 			}
 		}
 
 		this.contentNegotiationManager = new ContentNegotiationManager(strategies);
+
+		// Ensure media type mappings are available via ContentNegotiationManager#getMediaTypeMappings()
+		// independent of path extension or parameter strategies.
+
+		if (!CollectionUtils.isEmpty(this.mediaTypes) && !this.favorPathExtension && !this.favorParameter) {
+			this.contentNegotiationManager.addFileExtensionResolvers(
+					new MappingMediaTypeFileExtensionResolver(this.mediaTypes));
+		}
+
 		return this.contentNegotiationManager;
 	}
 

spring-web/src/main/java/org/springframework/web/accept/MappingMediaTypeFileExtensionResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -18,9 +18,11 @@ package org.springframework.web.accept;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.CopyOnWriteArrayList;
@@ -53,7 +55,7 @@ public class MappingMediaTypeFileExtensionResolver implements MediaTypeFileExten
 	 */
 	public MappingMediaTypeFileExtensionResolver(@Nullable Map<String, MediaType> mediaTypes) {
 		if (mediaTypes != null) {
-			List<String> allFileExtensions = new ArrayList<>();
+			Set<String> allFileExtensions = new HashSet<>(mediaTypes.size());
 			mediaTypes.forEach((extension, mediaType) -> {
 				String lowerCaseExtension = extension.toLowerCase(Locale.ENGLISH);
 				this.mediaTypes.put(lowerCaseExtension, mediaType);

spring-web/src/main/java/org/springframework/web/accept/PathExtensionContentNegotiationStrategy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -41,7 +41,11 @@ import org.springframework.web.util.UrlPathHelper;
  *
  * @author Rossen Stoyanchev
  * @since 3.2
+ * @deprecated as of 5.2.4. See class-level note in
+ * {@link ContentNegotiationManagerFactoryBean} on the deprecation of path
+ * extension config options.
  */
+@Deprecated
 public class PathExtensionContentNegotiationStrategy extends AbstractMappingContentNegotiationStrategy {
 
 	private UrlPathHelper urlPathHelper = new UrlPathHelper();

spring-web/src/main/java/org/springframework/web/accept/ServletPathExtensionContentNegotiationStrategy.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -34,7 +34,11 @@ import org.springframework.web.context.request.NativeWebRequest;
  *
  * @author Rossen Stoyanchev
  * @since 3.2
+ * @deprecated as of 5.2.4. See class-level note in
+ * {@link ContentNegotiationManagerFactoryBean} on the deprecation of path
+ * extension config options.
  */
+@Deprecated
 public class ServletPathExtensionContentNegotiationStrategy extends PathExtensionContentNegotiationStrategy {
 
 	private final ServletContext servletContext;

spring-web/src/test/java/org/springframework/web/accept/ContentNegotiationManagerFactoryBeanTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -21,6 +21,7 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Properties;
 
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -70,21 +71,29 @@ public class ContentNegotiationManagerFactoryBeanTests {
 
 		this.servletRequest.setRequestURI("/flower.gif");
 
-		assertThat(manager.resolveMediaTypes(this.webRequest)).as("Should be able to resolve file extensions by default").isEqualTo(Collections.singletonList(MediaType.IMAGE_GIF));
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.as("Should be able to resolve file extensions by default")
+				.isEqualTo(Collections.singletonList(MediaType.IMAGE_GIF));
 
 		this.servletRequest.setRequestURI("/flower.foobarbaz");
 
-		assertThat(manager.resolveMediaTypes(this.webRequest)).as("Should ignore unknown extensions by default").isEqualTo(ContentNegotiationStrategy.MEDIA_TYPE_ALL_LIST);
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.as("Should ignore unknown extensions by default")
+				.isEqualTo(ContentNegotiationStrategy.MEDIA_TYPE_ALL_LIST);
 
 		this.servletRequest.setRequestURI("/flower");
 		this.servletRequest.setParameter("format", "gif");
 
-		assertThat(manager.resolveMediaTypes(this.webRequest)).as("Should not resolve request parameters by default").isEqualTo(ContentNegotiationStrategy.MEDIA_TYPE_ALL_LIST);
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.as("Should not resolve request parameters by default")
+				.isEqualTo(ContentNegotiationStrategy.MEDIA_TYPE_ALL_LIST);
 
 		this.servletRequest.setRequestURI("/flower");
 		this.servletRequest.addHeader("Accept", MediaType.IMAGE_GIF_VALUE);
 
-		assertThat(manager.resolveMediaTypes(this.webRequest)).as("Should resolve Accept header by default").isEqualTo(Collections.singletonList(MediaType.IMAGE_GIF));
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.as("Should resolve Accept header by default")
+				.isEqualTo(Collections.singletonList(MediaType.IMAGE_GIF));
 	}
 
 	@Test
@@ -101,29 +110,33 @@ public class ContentNegotiationManagerFactoryBeanTests {
 
 		this.servletRequest.setRequestURI("/flower");
 		this.servletRequest.addParameter("format", "bar");
-		assertThat(manager.resolveMediaTypes(this.webRequest)).isEqualTo(Collections.singletonList(new MediaType("application", "bar")));
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.isEqualTo(Collections.singletonList(new MediaType("application", "bar")));
 
 	}
 
 	@Test
 	public void favorPath() throws Exception {
 		this.factoryBean.setFavorPathExtension(true);
-		this.factoryBean.addMediaTypes(Collections.singletonMap("bar", new MediaType("application", "bar")));
+		this.factoryBean.addMediaType("bar", new MediaType("application", "bar"));
 		this.factoryBean.afterPropertiesSet();
 		ContentNegotiationManager manager = this.factoryBean.getObject();
 
 		this.servletRequest.setRequestURI("/flower.foo");
-		assertThat(manager.resolveMediaTypes(this.webRequest)).isEqualTo(Collections.singletonList(new MediaType("application", "foo")));
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.isEqualTo(Collections.singletonList(new MediaType("application", "foo")));
 
 		this.servletRequest.setRequestURI("/flower.bar");
-		assertThat(manager.resolveMediaTypes(this.webRequest)).isEqualTo(Collections.singletonList(new MediaType("application", "bar")));
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.isEqualTo(Collections.singletonList(new MediaType("application", "bar")));
 
 		this.servletRequest.setRequestURI("/flower.gif");
-		assertThat(manager.resolveMediaTypes(this.webRequest)).isEqualTo(Collections.singletonList(MediaType.IMAGE_GIF));
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.isEqualTo(Collections.singletonList(MediaType.IMAGE_GIF));
 	}
 
 	@Test // SPR-10170
-	public void favorPathWithIgnoreUnknownPathExtensionTurnedOff() throws Exception {
+	public void favorPathWithIgnoreUnknownPathExtensionTurnedOff() {
 		this.factoryBean.setFavorPathExtension(true);
 		this.factoryBean.setIgnoreUnknownPathExtensions(false);
 		this.factoryBean.afterPropertiesSet();
@@ -139,10 +152,7 @@ public class ContentNegotiationManagerFactoryBeanTests {
 	@Test
 	public void favorParameter() throws Exception {
 		this.factoryBean.setFavorParameter(true);
-
+		this.factoryBean.addMediaType("json", MediaType.APPLICATION_JSON);
-		Map<String, MediaType> mediaTypes = new HashMap<>();
-		mediaTypes.put("json", MediaType.APPLICATION_JSON);
-		this.factoryBean.addMediaTypes(mediaTypes);
 
 		this.factoryBean.afterPropertiesSet();
 		ContentNegotiationManager manager = this.factoryBean.getObject();
@@ -150,11 +160,12 @@ public class ContentNegotiationManagerFactoryBeanTests {
 		this.servletRequest.setRequestURI("/flower");
 		this.servletRequest.addParameter("format", "json");
 
-		assertThat(manager.resolveMediaTypes(this.webRequest)).isEqualTo(Collections.singletonList(MediaType.APPLICATION_JSON));
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.isEqualTo(Collections.singletonList(MediaType.APPLICATION_JSON));
 	}
 
 	@Test // SPR-10170
-	public void favorParameterWithUnknownMediaType() throws HttpMediaTypeNotAcceptableException {
+	public void favorParameterWithUnknownMediaType() {
 		this.factoryBean.setFavorParameter(true);
 		this.factoryBean.afterPropertiesSet();
 		ContentNegotiationManager manager = this.factoryBean.getObject();
@@ -162,8 +173,52 @@ public class ContentNegotiationManagerFactoryBeanTests {
 		this.servletRequest.setRequestURI("/flower");
 		this.servletRequest.setParameter("format", "invalid");
 
-		assertThatExceptionOfType(HttpMediaTypeNotAcceptableException.class).isThrownBy(() ->
+		assertThatExceptionOfType(HttpMediaTypeNotAcceptableException.class)
-				manager.resolveMediaTypes(this.webRequest));
+				.isThrownBy(() -> manager.resolveMediaTypes(this.webRequest));
+	}
+
+	@Test
+	public void mediaTypeMappingsWithoutPathAndParameterStrategies() {
+
+		this.factoryBean.setFavorPathExtension(false);
+		this.factoryBean.setFavorParameter(false);
+
+		Properties properties = new Properties();
+		properties.put("JSon", "application/json");
+
+		this.factoryBean.setMediaTypes(properties);
+		this.factoryBean.addMediaType("pdF", MediaType.APPLICATION_PDF);
+		this.factoryBean.addMediaTypes(Collections.singletonMap("xML", MediaType.APPLICATION_XML));
+
+		ContentNegotiationManager manager = this.factoryBean.build();
+		assertThat(manager.getMediaTypeMappings())
+				.hasSize(3)
+				.containsEntry("json", MediaType.APPLICATION_JSON)
+				.containsEntry("pdf", MediaType.APPLICATION_PDF)
+				.containsEntry("xml", MediaType.APPLICATION_XML);
+	}
+
+	@Test
+	public void fileExtensions() {
+
+		this.factoryBean.setFavorPathExtension(false);
+		this.factoryBean.setFavorParameter(false);
+
+		Properties properties = new Properties();
+		properties.put("json", "application/json");
+		properties.put("pdf", "application/pdf");
+		properties.put("xml", "application/xml");
+		this.factoryBean.setMediaTypes(properties);
+
+		this.factoryBean.addMediaType("jsON", MediaType.APPLICATION_JSON);
+		this.factoryBean.addMediaType("pdF", MediaType.APPLICATION_PDF);
+
+		this.factoryBean.addMediaTypes(Collections.singletonMap("JSon", MediaType.APPLICATION_JSON));
+		this.factoryBean.addMediaTypes(Collections.singletonMap("xML", MediaType.APPLICATION_XML));
+
+		ContentNegotiationManager manager = this.factoryBean.build();
+		assertThat(manager.getAllFileExtensions()).containsExactlyInAnyOrder("json", "xml", "pdf");
+
 	}
 
 	@Test
@@ -175,7 +230,8 @@ public class ContentNegotiationManagerFactoryBeanTests {
 		this.servletRequest.setRequestURI("/flower");
 		this.servletRequest.addHeader("Accept", MediaType.IMAGE_GIF_VALUE);
 
-		assertThat(manager.resolveMediaTypes(this.webRequest)).isEqualTo(ContentNegotiationStrategy.MEDIA_TYPE_ALL_LIST);
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.isEqualTo(ContentNegotiationStrategy.MEDIA_TYPE_ALL_LIST);
 	}
 
 	@Test
@@ -210,10 +266,12 @@ public class ContentNegotiationManagerFactoryBeanTests {
 		this.factoryBean.afterPropertiesSet();
 		ContentNegotiationManager manager = this.factoryBean.getObject();
 
-		assertThat(manager.resolveMediaTypes(this.webRequest)).isEqualTo(Collections.singletonList(MediaType.APPLICATION_JSON));
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.isEqualTo(Collections.singletonList(MediaType.APPLICATION_JSON));
 
 		this.servletRequest.addHeader("Accept", MediaType.ALL_VALUE);
-		assertThat(manager.resolveMediaTypes(this.webRequest)).isEqualTo(Collections.singletonList(MediaType.APPLICATION_JSON));
+		assertThat(manager.resolveMediaTypes(this.webRequest))
+				.isEqualTo(Collections.singletonList(MediaType.APPLICATION_JSON));
 	}
 
 

spring-web/src/test/java/org/springframework/web/accept/MappingMediaTypeFileExtensionResolverTests.java

@@ -17,6 +17,7 @@
 package org.springframework.web.accept;
 
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
@@ -34,12 +35,14 @@ import static org.assertj.core.api.Assertions.assertThat;
  */
 public class MappingMediaTypeFileExtensionResolverTests {
 
-	private final Map<String, MediaType> mapping = Collections.singletonMap("json", MediaType.APPLICATION_JSON);
+	private static final Map<String, MediaType> DEFAULT_MAPPINGS =
-	private final MappingMediaTypeFileExtensionResolver resolver = new MappingMediaTypeFileExtensionResolver(this.mapping);
+			Collections.singletonMap("json", MediaType.APPLICATION_JSON);
+
 
 	@Test
 	public void resolveExtensions() {
-		List<String> extensions = this.resolver.resolveFileExtensions(MediaType.APPLICATION_JSON);
+		List<String> extensions = new MappingMediaTypeFileExtensionResolver(DEFAULT_MAPPINGS)
+				.resolveFileExtensions(MediaType.APPLICATION_JSON);
 
 		assertThat(extensions).hasSize(1);
 		assertThat(extensions.get(0)).isEqualTo("json");
@@ -47,20 +50,24 @@ public class MappingMediaTypeFileExtensionResolverTests {
 
 	@Test
 	public void resolveExtensionsNoMatch() {
-		List<String> extensions = this.resolver.resolveFileExtensions(MediaType.TEXT_HTML);
+		assertThat(new MappingMediaTypeFileExtensionResolver(DEFAULT_MAPPINGS)
-
+				.resolveFileExtensions(MediaType.TEXT_HTML)).isEmpty();
-		assertThat(extensions).isEmpty();
 	}
 
-	/**
+	@Test // SPR-13747
-	 * Unit test for SPR-13747 - ensures that reverse lookup of media type from media
-	 * type key is case-insensitive.
-	 */
-	@Test
 	public void lookupMediaTypeCaseInsensitive() {
-		MediaType mediaType = this.resolver.lookupMediaType("JSON");
+		assertThat(new MappingMediaTypeFileExtensionResolver(DEFAULT_MAPPINGS).lookupMediaType("JSON"))
-
+				.isEqualTo(MediaType.APPLICATION_JSON);
-		assertThat(mediaType).isEqualTo(MediaType.APPLICATION_JSON);
 	}
 
+	@Test
+	public void allFileExtensions() {
+		Map<String, MediaType> mappings = new HashMap<>();
+		mappings.put("json", MediaType.APPLICATION_JSON);
+		mappings.put("JsOn", MediaType.APPLICATION_JSON);
+		mappings.put("jSoN", MediaType.APPLICATION_JSON);
+
+		MappingMediaTypeFileExtensionResolver resolver = new MappingMediaTypeFileExtensionResolver(mappings);
+		assertThat(resolver.getAllFileExtensions()).containsExactly("json");
+	}
 }

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/ContentNegotiationConfigurer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -32,7 +32,6 @@ import org.springframework.web.accept.ContentNegotiationStrategy;
 import org.springframework.web.accept.FixedContentNegotiationStrategy;
 import org.springframework.web.accept.HeaderContentNegotiationStrategy;
 import org.springframework.web.accept.ParameterContentNegotiationStrategy;
-import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
 
 /**
  * Creates a {@code ContentNegotiationManager} and configures it with
@@ -52,7 +51,8 @@ import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
  * <tr>
  * <td>{@link #favorPathExtension}</td>
  * <td>true</td>
- * <td>{@link PathExtensionContentNegotiationStrategy}</td>
+ * <td>{@link org.springframework.web.accept.PathExtensionContentNegotiationStrategy
+ * PathExtensionContentNegotiationStrategy}</td>
  * <td>Enabled</td>
  * </tr>
  * <tr>
@@ -129,7 +129,11 @@ public class ContentNegotiationConfigurer {
 	 * <p>By default this is set to {@code true} in which case a request
 	 * for {@code /hotels.pdf} will be interpreted as a request for
 	 * {@code "application/pdf"} regardless of the 'Accept' header.
+	 * @deprecated as of 5.2.4. See class-level note in
+	 * {@link ContentNegotiationManagerFactoryBean} on the deprecation of path
+	 * extension config options.
 	 */
+	@Deprecated
 	public ContentNegotiationConfigurer favorPathExtension(boolean favorPathExtension) {
 		this.factory.setFavorPathExtension(favorPathExtension);
 		return this;
@@ -183,7 +187,11 @@ public class ContentNegotiationConfigurer {
 	 * to any media type. Setting this to {@code false} will result in an
 	 * {@code HttpMediaTypeNotAcceptableException} if there is no match.
 	 * <p>By default this is set to {@code true}.
+	 * @deprecated as of 5.2.4. See class-level note in
+	 * {@link ContentNegotiationManagerFactoryBean} on the deprecation of path
+	 * extension config options.
 	 */
+	@Deprecated
 	public ContentNegotiationConfigurer ignoreUnknownPathExtensions(boolean ignore) {
 		this.factory.setIgnoreUnknownPathExtensions(ignore);
 		return this;

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/PathMatchConfigurer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -22,6 +22,7 @@ import java.util.function.Predicate;
 
 import org.springframework.lang.Nullable;
 import org.springframework.util.PathMatcher;
+import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
 import org.springframework.web.util.UrlPathHelper;
 
 /**
@@ -37,7 +38,7 @@ import org.springframework.web.util.UrlPathHelper;
  *
  * @author Brian Clozel
  * @since 4.0.3
- * @see org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping
+ * @see RequestMappingHandlerMapping
  * @see org.springframework.web.servlet.handler.SimpleUrlHandlerMapping
  */
 public class PathMatchConfigurer {
@@ -46,10 +47,10 @@ public class PathMatchConfigurer {
 	private Boolean suffixPatternMatch;
 
 	@Nullable
-	private Boolean trailingSlashMatch;
+	private Boolean registeredSuffixPatternMatch;
 
 	@Nullable
-	private Boolean registeredSuffixPatternMatch;
+	private Boolean trailingSlashMatch;
 
 	@Nullable
 	private UrlPathHelper urlPathHelper;
@@ -66,22 +67,16 @@ public class PathMatchConfigurer {
 	 * requests. If enabled a method mapped to "/users" also matches to "/users.*".
 	 * <p>By default this is set to {@code true}.
 	 * @see #registeredSuffixPatternMatch
+	 * @deprecated as of 5.2.4. See class-level note in
+	 * {@link RequestMappingHandlerMapping} on the deprecation of path extension
+	 * config options.
 	 */
+	@Deprecated
 	public PathMatchConfigurer setUseSuffixPatternMatch(Boolean suffixPatternMatch) {
 		this.suffixPatternMatch = suffixPatternMatch;
 		return this;
 	}
 
-	/**
-	 * Whether to match to URLs irrespective of the presence of a trailing slash.
-	 * If enabled a method mapped to "/users" also matches to "/users/".
-	 * <p>The default value is {@code true}.
-	 */
-	public PathMatchConfigurer setUseTrailingSlashMatch(Boolean trailingSlashMatch) {
-		this.trailingSlashMatch = trailingSlashMatch;
-		return this;
-	}
-
 	/**
 	 * Whether suffix pattern matching should work only against path extensions
 	 * explicitly registered when you
@@ -90,12 +85,26 @@ public class PathMatchConfigurer {
 	 * avoid issues such as when a "." appears in the path for other reasons.
 	 * <p>By default this is set to "false".
 	 * @see WebMvcConfigurer#configureContentNegotiation
+	 * @deprecated as of 5.2.4. See class-level note in
+	 * {@link RequestMappingHandlerMapping} on the deprecation of path extension
+	 * config options.
 	 */
+	@Deprecated
 	public PathMatchConfigurer setUseRegisteredSuffixPatternMatch(Boolean registeredSuffixPatternMatch) {
 		this.registeredSuffixPatternMatch = registeredSuffixPatternMatch;
 		return this;
 	}
 
+	/**
+	 * Whether to match to URLs irrespective of the presence of a trailing slash.
+	 * If enabled a method mapped to "/users" also matches to "/users/".
+	 * <p>The default value is {@code true}.
+	 */
+	public PathMatchConfigurer setUseTrailingSlashMatch(Boolean trailingSlashMatch) {
+		this.trailingSlashMatch = trailingSlashMatch;
+		return this;
+	}
+
 	/**
 	 * Set the UrlPathHelper to use for resolution of lookup paths.
 	 * <p>Use this to override the default UrlPathHelper with a custom subclass,
@@ -137,21 +146,35 @@ public class PathMatchConfigurer {
 	}
 
 
+	/**
+	 * Whether to use registered suffixes for pattern matching.
+	 * @deprecated as of 5.2.4. See class-level note in
+	 * {@link RequestMappingHandlerMapping} on the deprecation of path extension
+	 * config options.
+	 */
 	@Nullable
+	@Deprecated
 	public Boolean isUseSuffixPatternMatch() {
 		return this.suffixPatternMatch;
 	}
 
+	/**
+	 * Whether to use registered suffixes for pattern matching.
+	 * @deprecated as of 5.2.4. See class-level note in
+	 * {@link RequestMappingHandlerMapping} on the deprecation of path extension
+	 * config options.
+	 */
+	@Nullable
+	@Deprecated
+	public Boolean isUseRegisteredSuffixPatternMatch() {
+		return this.registeredSuffixPatternMatch;
+	}
+
 	@Nullable
 	public Boolean isUseTrailingSlashMatch() {
 		return this.trailingSlashMatch;
 	}
 
-	@Nullable
-	public Boolean isUseRegisteredSuffixPatternMatch() {
-		return this.registeredSuffixPatternMatch;
-	}
-
 	@Nullable
 	public UrlPathHelper getUrlPathHelper() {
 		return this.urlPathHelper;

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/ResourceHandlerRegistry.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -151,6 +151,7 @@ public class ResourceHandlerRegistry {
 	 * of no registrations.
 	 */
 	@Nullable
+	@SuppressWarnings("deprecation")
 	protected AbstractHandlerMapping getHandlerMapping() {
 		if (this.registrations.isEmpty()) {
 			return null;

spring-webmvc/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurationSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -275,6 +275,7 @@ public class WebMvcConfigurationSupport implements ApplicationContextAware, Serv
 	 * requests to annotated controllers.
 	 */
 	@Bean
+	@SuppressWarnings("deprecation")
 	public RequestMappingHandlerMapping requestMappingHandlerMapping(
 			@Qualifier("mvcContentNegotiationManager") ContentNegotiationManager contentNegotiationManager,
 			@Qualifier("mvcConversionService") FormattingConversionService conversionService,

spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/condition/PatternsRequestCondition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -33,6 +33,7 @@ import org.springframework.util.AntPathMatcher;
 import org.springframework.util.PathMatcher;
 import org.springframework.util.StringUtils;
 import org.springframework.web.servlet.HandlerMapping;
+import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
 import org.springframework.web.util.UrlPathHelper;
 
 /**
@@ -58,23 +59,42 @@ public final class PatternsRequestCondition extends AbstractRequestCondition<Pat
 
 
 	/**
-	 * Creates a new instance with the given URL patterns.
+	 * Creates a new instance with the given URL patterns. Each pattern that is
-	 * Each pattern that is not empty and does not start with "/" is prepended with "/".
+	 * not empty and does not start with "/" is prepended with "/".
-	 * @param patterns 0 or more URL patterns; if 0 the condition will match to every request.
+	 * @param patterns 0 or more URL patterns; if 0 the condition will match to
+	 * every request.
 	 */
 	public PatternsRequestCondition(String... patterns) {
 		this(Arrays.asList(patterns), null, null, true, true, null);
 	}
 
 	/**
-	 * Additional constructor with flags for using suffix pattern (.*) and
+	 * Alternative constructor with additional, optional {@link UrlPathHelper},
-	 * trailing slash matches.
+	 * {@link PathMatcher}, and whether to automatically match trailing slashes.
+	 * @param patterns the URL patterns to use; if 0, the condition will match to every request.
+	 * @param urlPathHelper a {@link UrlPathHelper} for determining the lookup path for a request
+	 * @param pathMatcher a {@link PathMatcher} for pattern path matching
+	 * @param useTrailingSlashMatch whether to match irrespective of a trailing slash
+	 * @since 5.2.4
+	 */
+	public PatternsRequestCondition(String[] patterns, @Nullable UrlPathHelper urlPathHelper,
+			@Nullable PathMatcher pathMatcher, boolean useTrailingSlashMatch) {
+
+		this(Arrays.asList(patterns), urlPathHelper, pathMatcher, false, useTrailingSlashMatch, null);
+	}
+
+	/**
+	 * Alternative constructor with additional optional parameters.
 	 * @param patterns the URL patterns to use; if 0, the condition will match to every request.
 	 * @param urlPathHelper for determining the lookup path of a request
 	 * @param pathMatcher for path matching with patterns
 	 * @param useSuffixPatternMatch whether to enable matching by suffix (".*")
 	 * @param useTrailingSlashMatch whether to match irrespective of a trailing slash
+	 * @deprecated as of 5.2.4. See class-level note in
+	 * {@link RequestMappingHandlerMapping} on the deprecation of path extension
+	 * config options.
 	 */
+	@Deprecated
 	public PatternsRequestCondition(String[] patterns, @Nullable UrlPathHelper urlPathHelper,
 			@Nullable PathMatcher pathMatcher, boolean useSuffixPatternMatch, boolean useTrailingSlashMatch) {
 
@@ -82,15 +102,18 @@ public final class PatternsRequestCondition extends AbstractRequestCondition<Pat
 	}
 
 	/**
-	 * Creates a new instance with the given URL patterns.
+	 * Alternative constructor with additional optional parameters.
-	 * Each pattern that is not empty and does not start with "/" is pre-pended with "/".
 	 * @param patterns the URL patterns to use; if 0, the condition will match to every request.
 	 * @param urlPathHelper a {@link UrlPathHelper} for determining the lookup path for a request
 	 * @param pathMatcher a {@link PathMatcher} for pattern path matching
 	 * @param useSuffixPatternMatch whether to enable matching by suffix (".*")
 	 * @param useTrailingSlashMatch whether to match irrespective of a trailing slash
 	 * @param fileExtensions a list of file extensions to consider for path matching
+	 * @deprecated as of 5.2.4. See class-level note in
+	 * {@link RequestMappingHandlerMapping} on the deprecation of path extension
+	 * config options.
 	 */
+	@Deprecated
 	public PatternsRequestCondition(String[] patterns, @Nullable UrlPathHelper urlPathHelper,
 			@Nullable PathMatcher pathMatcher, boolean useSuffixPatternMatch,
 			boolean useTrailingSlashMatch, @Nullable List<String> fileExtensions) {

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -35,6 +35,7 @@ import org.springframework.web.servlet.mvc.condition.ProducesRequestCondition;
 import org.springframework.web.servlet.mvc.condition.RequestCondition;
 import org.springframework.web.servlet.mvc.condition.RequestConditionHolder;
 import org.springframework.web.servlet.mvc.condition.RequestMethodsRequestCondition;
+import org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping;
 import org.springframework.web.util.UrlPathHelper;
 
 /**
@@ -505,6 +506,7 @@ public final class RequestMappingInfo implements RequestCondition<RequestMapping
 		}
 
 		@Override
+		@SuppressWarnings("deprecation")
 		public RequestMappingInfo build() {
 			ContentNegotiationManager manager = this.options.getContentNegotiationManager();
 
@@ -600,14 +602,22 @@ public final class RequestMappingInfo implements RequestCondition<RequestMapping
 		 * Set whether to apply suffix pattern matching in PatternsRequestCondition.
 		 * <p>By default this is set to 'true'.
 		 * @see #setRegisteredSuffixPatternMatch(boolean)
+		 * @deprecated as of 5.2.4. See class-level note in
+		 * {@link RequestMappingHandlerMapping} on the deprecation of path
+		 * extension config options.
 		 */
+		@Deprecated
 		public void setSuffixPatternMatch(boolean suffixPatternMatch) {
 			this.suffixPatternMatch = suffixPatternMatch;
 		}
 
 		/**
 		 * Return whether to apply suffix pattern matching in PatternsRequestCondition.
+		 * @deprecated as of 5.2.4. See class-level note in
+		 * {@link RequestMappingHandlerMapping} on the deprecation of path
+		 * extension config options.
 		 */
+		@Deprecated
 		public boolean useSuffixPatternMatch() {
 			return this.suffixPatternMatch;
 		}
@@ -618,7 +628,12 @@ public final class RequestMappingInfo implements RequestCondition<RequestMapping
 		 * {@code suffixPatternMatch=true} and requires that a
 		 * {@link #setContentNegotiationManager} is also configured in order to
 		 * obtain the registered file extensions.
+		 * @deprecated as of 5.2.4. See class-level note in
+		 * {@link RequestMappingHandlerMapping} on the deprecation of path
+		 * extension config options; note also that in 5.3 the default for this
+		 * property switches from {@code false} to {@code true}.
 		 */
+		@Deprecated
 		public void setRegisteredSuffixPatternMatch(boolean registeredSuffixPatternMatch) {
 			this.registeredSuffixPatternMatch = registeredSuffixPatternMatch;
 			this.suffixPatternMatch = (registeredSuffixPatternMatch || this.suffixPatternMatch);
@@ -627,7 +642,11 @@ public final class RequestMappingInfo implements RequestCondition<RequestMapping
 		/**
 		 * Return whether suffix pattern matching should be restricted to registered
 		 * file extensions only.
+		 * @deprecated as of 5.2.4. See class-level note in
+		 * {@link RequestMappingHandlerMapping} on the deprecation of path
+		 * extension config options.
 		 */
+		@Deprecated
 		public boolean useRegisteredSuffixPatternMatch() {
 			return this.registeredSuffixPatternMatch;
 		}
@@ -636,8 +655,12 @@ public final class RequestMappingInfo implements RequestCondition<RequestMapping
 		 * Return the file extensions to use for suffix pattern matching. If
 		 * {@code registeredSuffixPatternMatch=true}, the extensions are obtained
 		 * from the configured {@code contentNegotiationManager}.
+		 * @deprecated as of 5.2.4. See class-level note in
+		 * {@link RequestMappingHandlerMapping} on the deprecation of path
+		 * extension config options.
 		 */
 		@Nullable
+		@Deprecated
 		public List<String> getFileExtensions() {
 			if (useRegisteredSuffixPatternMatch() && this.contentNegotiationManager != null) {
 				return this.contentNegotiationManager.getAllFileExtensions();

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

@@ -26,6 +26,7 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Set;
 
+import javax.servlet.ServletRequest;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
@@ -43,6 +44,7 @@ import org.springframework.http.HttpOutputMessage;
 import org.springframework.http.HttpRange;
 import org.springframework.http.HttpStatus;
 import org.springframework.http.MediaType;
+import org.springframework.http.MediaTypeFactory;
 import org.springframework.http.converter.GenericHttpMessageConverter;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.HttpMessageNotWritableException;
@@ -54,7 +56,6 @@ import org.springframework.util.CollectionUtils;
 import org.springframework.util.StringUtils;
 import org.springframework.web.HttpMediaTypeNotAcceptableException;
 import org.springframework.web.accept.ContentNegotiationManager;
-import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
 import org.springframework.web.context.request.NativeWebRequest;
 import org.springframework.web.context.request.ServletWebRequest;
 import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
@@ -102,8 +103,6 @@ public abstract class AbstractMessageConverterMethodProcessor extends AbstractMe
 
 	private final ContentNegotiationManager contentNegotiationManager;
 
-	private final PathExtensionContentNegotiationStrategy pathStrategy;
-
 	private final Set<String> safeExtensions = new HashSet<>();
 
 
@@ -133,17 +132,10 @@ public abstract class AbstractMessageConverterMethodProcessor extends AbstractMe
 		super(converters, requestResponseBodyAdvice);
 
 		this.contentNegotiationManager = (manager != null ? manager : new ContentNegotiationManager());
-		this.pathStrategy = initPathStrategy(this.contentNegotiationManager);
 		this.safeExtensions.addAll(this.contentNegotiationManager.getAllFileExtensions());
 		this.safeExtensions.addAll(WHITELISTED_EXTENSIONS);
 	}
 
-	private static PathExtensionContentNegotiationStrategy initPathStrategy(ContentNegotiationManager manager) {
-		Class<PathExtensionContentNegotiationStrategy> clazz = PathExtensionContentNegotiationStrategy.class;
-		PathExtensionContentNegotiationStrategy strategy = manager.getStrategy(clazz);
-		return (strategy != null ? strategy : new PathExtensionContentNegotiationStrategy());
-	}
-
 
 	/**
 	 * Creates a new {@link HttpOutputMessage} from the given {@link NativeWebRequest}.
@@ -481,26 +473,21 @@ public abstract class AbstractMessageConverterMethodProcessor extends AbstractMe
 				return true;
 			}
 		}
-		return safeMediaTypesForExtension(new ServletWebRequest(request), extension);
+		MediaType mediaType = resolveMediaType(request, extension);
+		return (mediaType != null && (safeMediaType(mediaType)));
 	}
 
-	private boolean safeMediaTypesForExtension(NativeWebRequest request, String extension) {
+	@Nullable
-		List<MediaType> mediaTypes = null;
+	private MediaType resolveMediaType(ServletRequest request, String extension) {
-		try {
+		MediaType result = null;
-			mediaTypes = this.pathStrategy.resolveMediaTypeKey(request, extension);
+		String rawMimeType = request.getServletContext().getMimeType("file." + extension);
+		if (StringUtils.hasText(rawMimeType)) {
+			result = MediaType.parseMediaType(rawMimeType);
 		}
-		catch (HttpMediaTypeNotAcceptableException ex) {
+		if (result == null || MediaType.APPLICATION_OCTET_STREAM.equals(result)) {
-			// Ignore
+			result = MediaTypeFactory.getMediaType("file." + extension).orElse(null);
 		}
-		if (CollectionUtils.isEmpty(mediaTypes)) {
+		return result;
-			return false;
-		}
-		for (MediaType mediaType : mediaTypes) {
-			if (!safeMediaType(mediaType)) {
-				return false;
-			}
-		}
-		return true;
 	}
 
 	private boolean safeMediaType(MediaType mediaType) {

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -59,6 +59,18 @@ import org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMappi
  * {@link RequestMapping @RequestMapping} annotations in
  * {@link Controller @Controller} classes.
  *
+ * <p><strong>Note:</strong></p> In 5.2.4,
+ * {@link #setUseSuffixPatternMatch(boolean) useSuffixPatternMatch} and
+ * {@link #setUseRegisteredSuffixPatternMatch(boolean) useRegisteredSuffixPatternMatch}
+ * are deprecated in order to discourage use of path extensions for request
+ * mapping and for content negotiation (with similar deprecations in
+ * {@link ContentNegotiationManager}). For further context, please read issue
+ * <a href="https://github.com/spring-projects/spring-framework/issues/24179">#24719</a>.
+ *
+ * <p>In 5.3, {@link #setUseRegisteredSuffixPatternMatch(boolean) useRegisteredSuffixPatternMatch}
+ * switches to being on by default so that path matching becomes constrained
+ * to registered suffixes only.
+ *
  * @author Arjen Poutsma
  * @author Rossen Stoyanchev
  * @author Sam Brannen
@@ -89,7 +101,10 @@ public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMappi
 	 * <p>The default value is {@code true}.
 	 * <p>Also see {@link #setUseRegisteredSuffixPatternMatch(boolean)} for
 	 * more fine-grained control over specific suffixes to allow.
+	 * @deprecated as of 5.2.4. See class level comment about deprecation of
+	 * path extension config options.
 	 */
+	@Deprecated
 	public void setUseSuffixPatternMatch(boolean useSuffixPatternMatch) {
 		this.useSuffixPatternMatch = useSuffixPatternMatch;
 	}
@@ -100,7 +115,11 @@ public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMappi
 	 * is generally recommended to reduce ambiguity and to avoid issues such as
 	 * when a "." appears in the path for other reasons.
 	 * <p>By default this is set to "false".
+	 * @deprecated as of 5.2.4. See class level comment about deprecation of
+	 * path extension config options note also that in 5.3 the default for this
+	 * property will switch from {@code false} to {@code true}.
 	 */
+	@Deprecated
 	public void setUseRegisteredSuffixPatternMatch(boolean useRegisteredSuffixPatternMatch) {
 		this.useRegisteredSuffixPatternMatch = useRegisteredSuffixPatternMatch;
 		this.useSuffixPatternMatch = (useRegisteredSuffixPatternMatch || this.useSuffixPatternMatch);
@@ -159,13 +178,14 @@ public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMappi
 	}
 
 	@Override
+	@SuppressWarnings("deprecation")
 	public void afterPropertiesSet() {
 		this.config = new RequestMappingInfo.BuilderConfiguration();
 		this.config.setUrlPathHelper(getUrlPathHelper());
 		this.config.setPathMatcher(getPathMatcher());
-		this.config.setSuffixPatternMatch(this.useSuffixPatternMatch);
+		this.config.setSuffixPatternMatch(useSuffixPatternMatch());
-		this.config.setTrailingSlashMatch(this.useTrailingSlashMatch);
+		this.config.setTrailingSlashMatch(useTrailingSlashMatch());
-		this.config.setRegisteredSuffixPatternMatch(this.useRegisteredSuffixPatternMatch);
+		this.config.setRegisteredSuffixPatternMatch(useRegisteredSuffixPatternMatch());
 		this.config.setContentNegotiationManager(getContentNegotiationManager());
 
 		super.afterPropertiesSet();
@@ -173,15 +193,21 @@ public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMappi
 
 
 	/**
-	 * Whether to use suffix pattern matching.
+	 * Whether to use registered suffixes for pattern matching.
+	 * @deprecated as of 5.2.4. See class-level note on the deprecation of path
+	 * extension config options.
 	 */
+	@Deprecated
 	public boolean useSuffixPatternMatch() {
 		return this.useSuffixPatternMatch;
 	}
 
 	/**
 	 * Whether to use registered suffixes for pattern matching.
+	 * @deprecated as of 5.2.4. See class-level note on the deprecation of path
+	 * extension config options.
 	 */
+	@Deprecated
 	public boolean useRegisteredSuffixPatternMatch() {
 		return this.useRegisteredSuffixPatternMatch;
 	}
@@ -195,8 +221,12 @@ public class RequestMappingHandlerMapping extends RequestMappingInfoHandlerMappi
 
 	/**
 	 * Return the file extensions to use for suffix pattern matching.
+	 * @deprecated as of 5.2.4. See class-level note on the deprecation of path
+	 * extension config options.
 	 */
 	@Nullable
+	@Deprecated
+	@SuppressWarnings("deprecation")
 	public List<String> getFileExtensions() {
 		return this.config.getFileExtensions();
 	}

spring-webmvc/src/main/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandler.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -24,6 +24,7 @@ import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import java.util.stream.Collectors;
 
@@ -43,6 +44,7 @@ import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
 import org.springframework.http.HttpRange;
 import org.springframework.http.MediaType;
+import org.springframework.http.MediaTypeFactory;
 import org.springframework.http.converter.ResourceHttpMessageConverter;
 import org.springframework.http.converter.ResourceRegionHttpMessageConverter;
 import org.springframework.http.server.ServletServerHttpRequest;
@@ -56,8 +58,6 @@ import org.springframework.util.StringUtils;
 import org.springframework.util.StringValueResolver;
 import org.springframework.web.HttpRequestHandler;
 import org.springframework.web.accept.ContentNegotiationManager;
-import org.springframework.web.accept.PathExtensionContentNegotiationStrategy;
-import org.springframework.web.accept.ServletPathExtensionContentNegotiationStrategy;
 import org.springframework.web.context.request.ServletWebRequest;
 import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.cors.CorsConfigurationSource;
@@ -129,8 +129,7 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 	@Nullable
 	private ContentNegotiationManager contentNegotiationManager;
 
-	@Nullable
+	private final Map<String, MediaType> mediaTypes = new HashMap<>(4);
-	private PathExtensionContentNegotiationStrategy contentNegotiationStrategy;
 
 	@Nullable
 	private CorsConfiguration corsConfiguration;
@@ -262,7 +261,11 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 	 * media types for resources being served. If the manager contains a path
 	 * extension strategy it will be checked for registered file extension.
 	 * @since 4.3
+	 * @deprecated as of 5.2.4 in favor of using {@link #setMediaTypes(Map)}
+	 * with mappings possibly obtained from
+	 * {@link ContentNegotiationManager#getMediaTypeMappings()}.
 	 */
+	@Deprecated
 	public void setContentNegotiationManager(@Nullable ContentNegotiationManager contentNegotiationManager) {
 		this.contentNegotiationManager = contentNegotiationManager;
 	}
@@ -270,12 +273,38 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 	/**
 	 * Return the configured content negotiation manager.
 	 * @since 4.3
+	 * @deprecated as of 5.2.4.
 	 */
 	@Nullable
+	@Deprecated
 	public ContentNegotiationManager getContentNegotiationManager() {
 		return this.contentNegotiationManager;
 	}
 
+	/**
+	 * Add mappings between file extensions, extracted from the filename of a
+	 * static {@link Resource}, and corresponding media type  to set on the
+	 * response.
+	 * <p>Use of this method is typically not necessary since mappings are
+	 * otherwise determined via
+	 * {@link javax.servlet.ServletContext#getMimeType(String)} or via
+	 * {@link MediaTypeFactory#getMediaType(Resource)}.
+	 * @param mediaTypes media type mappings
+	 * @since 5.2.4
+	 */
+	public void setMediaTypes(Map<String, MediaType> mediaTypes) {
+		mediaTypes.forEach((ext, mediaType) ->
+				this.mediaTypes.put(ext.toLowerCase(Locale.ENGLISH), mediaType));
+	}
+
+	/**
+	 * Return the {@link #setMediaTypes(Map) configured} media types.
+	 * @since 5.2.4
+	 */
+	public Map<String, MediaType> getMediaTypes() {
+		return this.mediaTypes;
+	}
+
 	/**
 	 * Specify the CORS configuration for resources served by this handler.
 	 * <p>By default this is not set in which allows cross-origin requests.
@@ -344,7 +373,17 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 			this.resourceRegionHttpMessageConverter = new ResourceRegionHttpMessageConverter();
 		}
 
-		this.contentNegotiationStrategy = initContentNegotiationStrategy();
+		ContentNegotiationManager manager = getContentNegotiationManager();
+		if (manager != null) {
+			setMediaTypes(manager.getMediaTypeMappings());
+		}
+
+		@SuppressWarnings("deprecation")
+		org.springframework.web.accept.PathExtensionContentNegotiationStrategy strategy =
+				initContentNegotiationStrategy();
+		if (strategy != null) {
+			setMediaTypes(strategy.getMediaTypes());
+		}
 	}
 
 	private void resolveResourceLocations() {
@@ -412,26 +451,20 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 	}
 
 	/**
-	 * Initialize the content negotiation strategy depending on the {@code ContentNegotiationManager}
+	 * Initialize the strategy to use to determine the media type for a resource.
-	 * setup and the availability of a {@code ServletContext}.
+	 * @deprecated as of 5.2.4 this method returns {@code null}, and if a
-	 * @see ServletPathExtensionContentNegotiationStrategy
+	 * sub-class returns an actual instance,the instance is used only as a
-	 * @see PathExtensionContentNegotiationStrategy
+	 * source of media type mappings, if it contains any. Please, use
+	 * {@link #setMediaTypes(Map)} instead, or if you need to change behavior,
+	 * you can override {@link #getMediaType(HttpServletRequest, Resource)}.
 	 */
-	protected PathExtensionContentNegotiationStrategy initContentNegotiationStrategy() {
+	@Nullable
-		Map<String, MediaType> mediaTypes = null;
+	@Deprecated
-		if (getContentNegotiationManager() != null) {
+	@SuppressWarnings("deprecation")
-			PathExtensionContentNegotiationStrategy strategy =
+	protected org.springframework.web.accept.PathExtensionContentNegotiationStrategy initContentNegotiationStrategy() {
-					getContentNegotiationManager().getStrategy(PathExtensionContentNegotiationStrategy.class);
+		return null;
-			if (strategy != null) {
-				mediaTypes = new HashMap<>(strategy.getMediaTypes());
-			}
-		}
-		return (getServletContext() != null ?
-				new ServletPathExtensionContentNegotiationStrategy(getServletContext(), mediaTypes) :
-				new PathExtensionContentNegotiationStrategy(mediaTypes));
 	}
 
-
 	/**
 	 * Processes a resource request.
 	 * <p>Checks for the existence of the requested resource in the configured list of locations.
@@ -659,17 +692,40 @@ public class ResourceHttpRequestHandler extends WebContentGenerator
 
 	/**
 	 * Determine the media type for the given request and the resource matched
-	 * to it. This implementation tries to determine the MediaType based on the
+	 * to it. This implementation tries to determine the MediaType using one of
-	 * file extension of the Resource via
+	 * the following lookups based on the resource filename and its path
-	 * {@link ServletPathExtensionContentNegotiationStrategy#getMediaTypeForResource}.
+	 * extension:
+	 * <ol>
+	 * <li>{@link javax.servlet.ServletContext#getMimeType(String)}
+	 * <li>{@link #getMediaTypes()}
+	 * <li>{@link MediaTypeFactory#getMediaType(String)}
+	 * </ol>
 	 * @param request the current request
 	 * @param resource the resource to check
 	 * @return the corresponding media type, or {@code null} if none found
 	 */
 	@Nullable
 	protected MediaType getMediaType(HttpServletRequest request, Resource resource) {
-		return (this.contentNegotiationStrategy != null ?
+		MediaType result = null;
-				this.contentNegotiationStrategy.getMediaTypeForResource(resource) : null);
+		String mimeType = request.getServletContext().getMimeType(resource.getFilename());
+		if (StringUtils.hasText(mimeType)) {
+			result = MediaType.parseMediaType(mimeType);
+		}
+		if (result == null || MediaType.APPLICATION_OCTET_STREAM.equals(result)) {
+			MediaType mediaType = null;
+			String filename = resource.getFilename();
+			String ext = StringUtils.getFilenameExtension(filename);
+			if (ext != null) {
+				mediaType = this.mediaTypes.get(ext.toLowerCase(Locale.ENGLISH));
+			}
+			if (mediaType == null) {
+				mediaType = MediaTypeFactory.getMediaType(filename).orElse(null);
+			}
+			if (mediaType != null) {
+				result = mediaType;
+			}
+		}
+		return result;
 	}
 
 	/**

spring-webmvc/src/test/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandlerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -74,13 +74,15 @@ public class ResourceHttpRequestHandlerTests {
 		paths.add(new ClassPathResource("testalternatepath/", getClass()));
 		paths.add(new ClassPathResource("META-INF/resources/webjars/"));
 
+		TestServletContext servletContext = new TestServletContext();
+
 		this.handler = new ResourceHttpRequestHandler();
 		this.handler.setLocations(paths);
 		this.handler.setCacheSeconds(3600);
-		this.handler.setServletContext(new TestServletContext());
+		this.handler.setServletContext(servletContext);
 		this.handler.afterPropertiesSet();
 
-		this.request = new MockHttpServletRequest("GET", "");
+		this.request = new MockHttpServletRequest(servletContext, "GET", "");
 		this.response = new MockHttpServletResponse();
 	}
 
@@ -283,15 +285,12 @@ public class ResourceHttpRequestHandlerTests {
 
 	@Test  // SPR-14368
 	public void getResourceWithMediaTypeResolvedThroughServletContext() throws Exception {
+
 		MockServletContext servletContext = new MockServletContext() {
 			@Override
 			public String getMimeType(String filePath) {
 				return "foo/bar";
 			}
-			@Override
-			public String getVirtualServerName() {
-				return "";
-			}
 		};
 
 		List<Resource> paths = Collections.singletonList(new ClassPathResource("test/", getClass()));
@@ -300,8 +299,9 @@ public class ResourceHttpRequestHandlerTests {
 		handler.setLocations(paths);
 		handler.afterPropertiesSet();
 
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		MockHttpServletRequest request = new MockHttpServletRequest(servletContext, "GET", "");
-		handler.handleRequest(this.request, this.response);
+		request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
+		handler.handleRequest(request, this.response);
 
 		assertThat(this.response.getContentType()).isEqualTo("foo/bar");
 		assertThat(this.response.getContentAsString()).isEqualTo("h1 { color:red; }");

src/docs/asciidoc/web/webmvc.adoc

@@ -1683,6 +1683,18 @@ the issues that come with file extensions. Alternatively, if you must use file e
 restricting them to a list of explicitly registered extensions through the
 `mediaTypes` property of <<mvc-config-content-negotiation,ContentNegotiationConfigurer>>.
 
+[INFO]
+====
+Starting in 5.2.4, path extension related options for request mapping in
+{api-spring-framework}/org/springframework/web/servlet/mvc/method/annotation/RequestMappingHandlerMapping.java[RequestMappingHandlerMapping]
+and for content negotiation in
+{api-spring-framework}/org.springframework.web.accept/ContentNegotiationManagerFactoryBean.java[ContentNegotiationManagerFactoryBean]
+are deprecated. See Spring Framework issue
+https://github.com/spring-projects/spring-framework/issues/24179[#24179] and related
+issues for further plans.
+====
+
+
 
 [[mvc-ann-requestmapping-rfd]]
 ==== Suffix Match and RFD
@@ -5779,13 +5791,11 @@ The following example shows how to customize path matching in Java configuration
 		@Override
 		public void configurePathMatch(PathMatchConfigurer configurer) {
 			configurer
-				.setUseSuffixPatternMatch(true)
 				.setUseTrailingSlashMatch(false)
 				.setUseRegisteredSuffixPatternMatch(true)
 				.setPathMatcher(antPathMatcher())
 				.setUrlPathHelper(urlPathHelper())
-				.addPathPrefix("/api",
+				.addPathPrefix("/api", HandlerTypePredicate.forAnnotation(RestController.class));
-						HandlerTypePredicate.forAnnotation(RestController.class));
 		}
 
 		@Bean
@@ -5813,8 +5823,7 @@ The following example shows how to customize path matching in Java configuration
 				.setUseRegisteredSuffixPatternMatch(true)
 				.setPathMatcher(antPathMatcher())
 				.setUrlPathHelper(urlPathHelper())
-				.addPathPrefix("/api",
+				.addPathPrefix("/api", HandlerTypePredicate.forAnnotation(RestController::class.java))
-						HandlerTypePredicate.forAnnotation(RestController::class.java))
 		}
 
 		@Bean
@@ -5835,7 +5844,6 @@ The following example shows how to achieve the same configuration in XML:
 ----
 	<mvc:annotation-driven>
 		<mvc:path-matching
-			suffix-pattern="true"
 			trailing-slash="false"
 			registered-suffixes-only="true"
 			path-helper="pathHelper"