Uses Charset instead of String in MimeType.equals()

Prior to this commit, Spring's MimeType checked for equality between
two MIME types based on the equality of their properties maps; however,
the properties maps contain string representations of the "charset"
values. Thus, "UTF-8" is never equal to "utf-8" which breaks the
contract for character set names which must be compared in a
case-insensitive manner.

This commit addresses this issue by ensuring that "charset" properties
in MimeType instances are compared as Java Charset instances, thereby
ignoring case when checking for equality between charset names.

Issue: SPR-13157

Author: sbrannen

spring-core/src/main/java/org/springframework/util/MimeType.java

@@ -25,6 +25,7 @@
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.TreeSet;
 
 /**
@@ -430,7 +431,37 @@ public boolean equals(Object other) {
 		MimeType otherType = (MimeType) other;
 		return (this.type.equalsIgnoreCase(otherType.type) &&
 				this.subtype.equalsIgnoreCase(otherType.subtype) &&
-				this.parameters.equals(otherType.parameters));
+				parametersAreEqual(otherType));
+	}
+
+	/**
+	 * Determine if the parameters in this {@code MimeType} and the supplied
+	 * {@code MimeType} are equal, performing case-insensitive comparisons
+	 * for {@link Charset}s.
+	 * @since 4.2
+	 */
+	private boolean parametersAreEqual(MimeType that) {
+		if (this.parameters.size() != that.parameters.size()) {
+			return false;
+		}
+
+		for (Entry<String, String> entry : this.parameters.entrySet()) {
+			String key = entry.getKey();
+			if (!that.parameters.containsKey(key)) {
+				return false;
+			}
+
+			if (PARAM_CHARSET.equals(key)) {
+				if (!ObjectUtils.nullSafeEquals(this.getCharSet(), that.getCharSet())) {
+					return false;
+				}
+			}
+			else if (!ObjectUtils.nullSafeEquals(this.parameters.get(key), that.parameters.get(key))) {
+				return false;
+			}
+		}
+
+		return true;
 	}
 
 	@Override

spring-core/src/test/java/org/springframework/util/MimeTypeTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -27,15 +27,18 @@
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.support.DefaultConversionService;
 
+import static java.util.Collections.singletonMap;
 import static org.junit.Assert.*;
 
 /**
+ * Unit tests for {@link MimeType}.
+ *
  * @author Arjen Poutsma
  * @author Juergen Hoeller
+ * @author Sam Brannen
  */
 public class MimeTypeTests {
 
-
 	@Test(expected = IllegalArgumentException.class)
 	public void slashInSubtype() {
 		new MimeType("text", "/");
@@ -85,7 +88,7 @@ public void parseQuotedCharset() {
 	}
 
 	@Test
-	public void testWithConversionService() {
+	public void withConversionService() {
 		ConversionService conversionService = new DefaultConversionService();
 		assertTrue(conversionService.canConvert(String.class, MimeType.class));
 		MimeType mimeType = MimeType.valueOf("application/xml");
@@ -211,16 +214,18 @@ public void parseMimeTypeIllegalCharset() {
 		MimeTypeUtils.parseMimeType("text/html; charset=foo-bar");
 	}
 
-	// SPR-8917
-
+	/**
+	 * SPR-8917
+	 */
 	@Test
 	public void parseMimeTypeQuotedParameterValue() {
 		MimeType mimeType = MimeTypeUtils.parseMimeType("audio/*;attr=\"v>alue\"");
 		assertEquals("\"v>alue\"", mimeType.getParameter("attr"));
 	}
 
-	// SPR-8917
-
+	/**
+	 * SPR-8917
+	 */
 	@Test
 	public void parseMimeTypeSingleQuotedParameterValue() {
 		MimeType mimeType = MimeTypeUtils.parseMimeType("audio/*;attr='v>alue'");
@@ -249,7 +254,7 @@ public void compareTo() {
 		MimeType audioBasic = new MimeType("audio", "basic");
 		MimeType audio = new MimeType("audio");
 		MimeType audioWave = new MimeType("audio", "wave");
-		MimeType audioBasicLevel = new MimeType("audio", "basic", Collections.singletonMap("level", "1"));
+		MimeType audioBasicLevel = new MimeType("audio", "basic", singletonMap("level", "1"));
 
 		// equal
 		assertEquals("Invalid comparison result", 0, audioBasic.compareTo(audioBasic));
@@ -284,16 +289,27 @@ public void compareToCaseSensitivity() {
 		assertEquals("Invalid comparison result", 0, m1.compareTo(m2));
 		assertEquals("Invalid comparison result", 0, m2.compareTo(m1));
 
-		m1 = new MimeType("audio", "basic", Collections.singletonMap("foo", "bar"));
-		m2 = new MimeType("audio", "basic", Collections.singletonMap("Foo", "bar"));
+		m1 = new MimeType("audio", "basic", singletonMap("foo", "bar"));
+		m2 = new MimeType("audio", "basic", singletonMap("Foo", "bar"));
 		assertEquals("Invalid comparison result", 0, m1.compareTo(m2));
 		assertEquals("Invalid comparison result", 0, m2.compareTo(m1));
 
-		m1 = new MimeType("audio", "basic", Collections.singletonMap("foo", "bar"));
-		m2 = new MimeType("audio", "basic", Collections.singletonMap("foo", "Bar"));
+		m1 = new MimeType("audio", "basic", singletonMap("foo", "bar"));
+		m2 = new MimeType("audio", "basic", singletonMap("foo", "Bar"));
 		assertTrue("Invalid comparison result", m1.compareTo(m2) != 0);
 		assertTrue("Invalid comparison result", m2.compareTo(m1) != 0);
 	}
 
+	/**
+	 * SPR-13157
+	 * @since 4.2
+	 */
+	@Test
+	public void equalsIsCaseInsensitiveForCharsets() {
+		MimeType m1 = new MimeType("text", "plain", singletonMap("charset", "UTF-8"));
+		MimeType m2 = new MimeType("text", "plain", singletonMap("charset", "utf-8"));
+		assertEquals(m1, m2);
+		assertEquals(m2, m1);
+	}
 
 }

spring-web/src/test/java/org/springframework/web/client/AbstractJettyServerTestCase.java

@@ -56,7 +56,7 @@ public class AbstractJettyServerTestCase {
 
 	protected static final String baseUrl = "http://localhost:" + port;
 
-	protected static final MediaType textContentType = new MediaType("text", "plain", Collections.singletonMap("charset", "utf-8"));
+	protected static final MediaType textContentType = new MediaType("text", "plain", Collections.singletonMap("charset", "UTF-8"));
 
 	protected static final MediaType jsonContentType = new MediaType("application", "json", Collections.singletonMap("charset", "utf-8"));