Add trailing slash support to AbstractUrlHandlerMapping

Issue: SPR-12818

spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractUrlHandlerMapping.java

@@ -54,6 +54,8 @@ public abstract class AbstractUrlHandlerMapping extends AbstractHandlerMapping {
 
 	private Object rootHandler;
 
+	private boolean useTrailingSlashMatch = false;
+
 	private boolean lazyInitHandlers = false;
 
 	private final Map<String, Object> handlerMap = new LinkedHashMap<String, Object>();
@@ -76,6 +78,22 @@ public abstract class AbstractUrlHandlerMapping extends AbstractHandlerMapping {
 		return this.rootHandler;
 	}
 
+	/**
+	 * Whether to match to URLs irrespective of the presence of a trailing slash.
+	 * If enabled a URL pattern such as "/users" also matches to "/users/".
+	 * <p>The default value is {@code false}.
+	 */
+	public void setUseTrailingSlashMatch(boolean useTrailingSlashMatch) {
+		this.useTrailingSlashMatch = useTrailingSlashMatch;
+	}
+
+	/**
+	 * Whether to match to URLs irrespective of the presence of a trailing slash.
+	 */
+	public boolean useTrailingSlashMatch() {
+		return this.useTrailingSlashMatch;
+	}
+
 	/**
 	 * Set whether to lazily initialize handlers. Only applicable to
 	 * singleton handlers, as prototypes are always lazily initialized.
@@ -159,6 +177,11 @@ public abstract class AbstractUrlHandlerMapping extends AbstractHandlerMapping {
 			if (getPathMatcher().match(registeredPattern, urlPath)) {
 				matchingPatterns.add(registeredPattern);
 			}
+			else if (useTrailingSlashMatch()) {
+				if (!registeredPattern.endsWith("/") && getPathMatcher().match(registeredPattern + "/", urlPath)) {
+					matchingPatterns.add(registeredPattern +"/");
+				}
+			}
 		}
 		String bestPatternMatch = null;
 		Comparator<String> patternComparator = getPathMatcher().getPatternComparator(urlPath);
@@ -171,6 +194,10 @@ public abstract class AbstractUrlHandlerMapping extends AbstractHandlerMapping {
 		}
 		if (bestPatternMatch != null) {
 			handler = this.handlerMap.get(bestPatternMatch);
+			if (handler == null) {
+				Assert.isTrue(bestPatternMatch.endsWith("/"));
+				handler = this.handlerMap.get(bestPatternMatch.substring(0, bestPatternMatch.length() - 1));
+			}
 			// Bean name or resolved handler?
 			if (handler instanceof String) {
 				String handlerName = (String) handler;

spring-webmvc/src/test/java/org/springframework/web/servlet/handler/SimpleUrlHandlerMappingTests.java

@@ -110,6 +110,11 @@ public class SimpleUrlHandlerMappingTests {
 		assertTrue("Handler is correct bean", hec != null && hec.getHandler() == otherBean);
 		assertEquals("welcome.x", req.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE));
 
+		req = new MockHttpServletRequest("GET", "/welcome/");
+		hec = getHandler(hm, req);
+		assertTrue("Handler is correct bean", hec != null && hec.getHandler() == otherBean);
+		assertEquals("welcome", req.getAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE));
+
 		req = new MockHttpServletRequest("GET", "/");
 		req.setServletPath("/welcome.html");
 		hec = getHandler(hm, req);

spring-webmvc/src/test/resources/org/springframework/web/servlet/handler/map2.xml

@@ -6,6 +6,7 @@
 	<bean id="urlMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
 		<property name="defaultHandler"><ref local="starController"/></property>
 		<property name="rootHandler"><ref local="mainController"/></property>
+		<property name="useTrailingSlashMatch" value="true"/>
 		<property name="urlMap">
 			<map>
 				<entry key="/welcome*"><ref local="otherController"/></entry>
@@ -22,6 +23,7 @@
 	<bean id="urlMappingWithProps" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
 		<property name="defaultHandler"><ref local="starController"/></property>
 		<property name="rootHandler"><ref local="mainController"/></property>
+		<property name="useTrailingSlashMatch" value="true"/>
 		<property name="mappings"><ref local="propsForUrlMapping2"/></property>
 	</bean>