Allow file locations for resource handling

Prior to this change, location checks for serving resources would append
`/` to the location path it didn't already have one.

This commit makes sure not to append a `/` if the provided location is
actually a file.

Issue: SPR-12747

Author: bclozel

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

@@ -315,6 +315,9 @@ else if (resource instanceof ServletContextResource) {
 			resourcePath = resource.getURL().getPath();
 			locationPath = location.getURL().getPath();
 		}
+		if(locationPath.equals(resourcePath)) {
+			return true;
+		}
 		locationPath = (locationPath.endsWith("/") ||
 				!StringUtils.hasLength(locationPath) ? locationPath : locationPath + "/");
 		if (!resourcePath.startsWith(locationPath)) {

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

@@ -280,6 +280,22 @@ public void resourceNotFound() throws Exception {
 	}
 
 
+	// SPR-12747
+	@Test
+	public void getResourceWithResourceLocation() throws Exception {
+		List<Resource> resourcePaths = new ArrayList<Resource>();
+		resourcePaths.add(new ClassPathResource("test/foo.css", getClass()));
+		this.handler.setLocations(resourcePaths);
+		MockHttpServletRequest request = new MockHttpServletRequest();
+		request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/foo.css");
+		request.setMethod("GET");
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		handler.handleRequest(request, response);
+		assertEquals("text/css", response.getContentType());
+		assertEquals(17, response.getContentLength());
+	}
+
+
 	private static class TestServletContext extends MockServletContext {
 
 		@Override