Merge pull request #32101 from terminux

* pr/32101:
  Polish 'Align MimeMappings with Tomcat's defaults'
  Align MimeMappings with Tomcat's defaults

Closes gh-32101

Author: philwebb

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatEmbeddedContext.java

@@ -17,6 +17,7 @@
 package org.springframework.boot.web.embedded.tomcat;
 
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
@@ -30,6 +31,7 @@
 import org.apache.catalina.core.StandardWrapper;
 import org.apache.catalina.session.ManagerBase;
 
+import org.springframework.boot.web.server.MimeMappings;
 import org.springframework.boot.web.server.WebServerException;
 import org.springframework.util.ClassUtils;
 
@@ -44,6 +46,8 @@ class TomcatEmbeddedContext extends StandardContext {
 
 	private TomcatStarter starter;
 
+	private MimeMappings mimeMappings;
+
 	@Override
 	public boolean loadOnStartup(Container[] children) {
 		// deferred until later (see deferredLoadOnStartup)
@@ -118,4 +122,27 @@ TomcatStarter getStarter() {
 		return this.starter;
 	}
 
+	void setMimeMappings(MimeMappings mimeMappings) {
+		this.mimeMappings = mimeMappings;
+	}
+
+	@Override
+	public String[] findMimeMappings() {
+		List<String> mappings = new ArrayList<>();
+		mappings.addAll(Arrays.asList(super.findMimeMappings()));
+		if (this.mimeMappings != null) {
+			this.mimeMappings.forEach((mapping) -> mappings.add(mapping.getExtension()));
+		}
+		return mappings.toArray(String[]::new);
+	}
+
+	@Override
+	public String findMimeMapping(String extension) {
+		String mimeMapping = super.findMimeMapping(extension);
+		if (mimeMapping != null) {
+			return mimeMapping;
+		}
+		return (this.mimeMappings != null) ? this.mimeMappings.get(extension) : null;
+	}
+
 }

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatServletWebServerFactory.java

@@ -389,9 +389,7 @@ protected void configureContext(Context context, ServletContextInitializer[] ini
 			tomcatErrorPage.setExceptionType(errorPage.getExceptionName());
 			context.addErrorPage(tomcatErrorPage);
 		}
-		for (MimeMappings.Mapping mapping : getMimeMappings()) {
-			context.addMimeMapping(mapping.getExtension(), mapping.getMimeType());
-		}
+		setMimeMappings(context);
 		configureSession(context);
 		configureCookieProcessor(context);
 		new DisableReferenceClearingContextCustomizer().customize(context);
@@ -423,6 +421,16 @@ private void configureSession(Context context) {
 		}
 	}
 
+	private void setMimeMappings(Context context) {
+		if (context instanceof TomcatEmbeddedContext embeddedContext) {
+			embeddedContext.setMimeMappings(getMimeMappings());
+			return;
+		}
+		for (MimeMappings.Mapping mapping : getMimeMappings()) {
+			context.addMimeMapping(mapping.getExtension(), mapping.getMimeType());
+		}
+	}
+
 	private void configureCookieProcessor(Context context) {
 		SameSite sessionSameSite = getSession().getCookie().getSameSite();
 		List<CookieSameSiteSupplier> suppliers = new ArrayList<>();