Polishing contribution

See gh-24074

spring-test/src/main/java/org/springframework/mock/web/MockMultipartHttpServletRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -124,16 +124,16 @@ public String getMultipartContentType(String paramOrFileName) {
 		if (file != null) {
 			return file.getContentType();
 		}
-
 		try {
 			Part part = getPart(paramOrFileName);
 			if (part != null) {
 				return part.getContentType();
 			}
-		} catch (ServletException | IOException e) {
-			throw new IllegalStateException("Cannot extract content type from multipart request.", e);
 		}
-
+		catch (ServletException | IOException ex) {
+			// Should never happen (we're not actually parsing)
+			throw new IllegalStateException(ex);
+		}
 		return null;
 	}
 

spring-web/src/test/java/org/springframework/mock/web/test/MockMultipartHttpServletRequest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2019 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.
@@ -16,13 +16,16 @@
 
 package org.springframework.mock.web.test;
 
+import java.io.IOException;
 import java.util.Collections;
 import java.util.Enumeration;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 
 import javax.servlet.ServletContext;
+import javax.servlet.ServletException;
+import javax.servlet.http.Part;
 
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.HttpMethod;
@@ -121,9 +124,17 @@ public String getMultipartContentType(String paramOrFileName) {
 		if (file != null) {
 			return file.getContentType();
 		}
-		else {
-			return null;
+		try {
+			Part part = getPart(paramOrFileName);
+			if (part != null) {
+				return part.getContentType();
+			}
+		}
+		catch (ServletException | IOException ex) {
+			// Should never happen (we're not actually parsing)
+			throw new IllegalStateException(ex);
 		}
+		return null;
 	}
 
 	@Override