SPR-8863 Add RequestContext.getPathToServlet() method.

This method allows a view to access the combined context path and
servlet mapping path for prefixing URLs without having to specify
the literal part of a servlet mapping such as "/main/*") 
explicitly everywhere. For example:

${requestContext.pathToServlet}/css/main.css

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/config/annotation/WebMvcConfigurationSupport.java

@@ -464,9 +464,14 @@ public abstract class WebMvcConfigurationSupport implements ApplicationContextAw
 	}
 
 	/**
-	 * Returns a {@link HandlerExceptionResolverComposite} that contains a list
-	 * of exception resolvers. To customize the list of exception resolvers,
-	 * consider overriding {@link #configureHandlerExceptionResolvers(List)}.
+	 * Returns a {@link HandlerExceptionResolverComposite} containing a list
+	 * of exception resolvers obtained either through 
+	 * {@link #configureHandlerExceptionResolvers(List)} or through
+	 * {@link #addDefaultHandlerExceptionResolvers(List)}.
+	 * <p><strong>Note:</strong> This method cannot be made final due to CGLib
+	 * constraints. Rather than overriding it, consider overriding
+	 * {@link #configureHandlerExceptionResolvers(List)}, which allows 
+	 * providing a list of resolvers.
 	 */
 	@Bean
 	public HandlerExceptionResolver handlerExceptionResolver() throws Exception {

org.springframework.web.servlet/src/main/java/org/springframework/web/servlet/support/RequestContext.java

@@ -417,6 +417,21 @@ public class RequestContext {
 		return url;
 	}
 
+	/**
+	 * Return the path to URL mappings within the current servlet including the 
+	 * context path and the servlet path of the original request. This is useful
+	 * for building links to other resources within the application where a 
+	 * servlet mapping of the style {@code "/main/*"} is used.
+	 * <p>Delegates to the UrlPathHelper for decoding the context path.
+	 * @see javax.servlet.http.HttpServletRequest#getContextPath
+	 * @see javax.servlet.http.HttpServletRequest#getServletPath()
+	 * @see #getUrlPathHelper
+	 */
+	public String getPathToServlet() {
+		return this.urlPathHelper.getOriginatingContextPath(this.request)
+				+ this.urlPathHelper.getOriginatingServletPath(this.request);
+	}
+
 	/**
 	 * Return the request URI of the original request, that is, the invoked URL without parameters. This is particularly
 	 * useful as HTML form action target, possibly in combination with the original query string. <p><b>Note this

org.springframework.web.servlet/src/test/java/org/springframework/web/servlet/support/RequestContextTests.java

@@ -27,12 +27,13 @@ import org.springframework.mock.web.MockHttpServletResponse;
 import org.springframework.mock.web.MockServletContext;
 import org.springframework.web.context.WebApplicationContext;
 import org.springframework.web.context.support.GenericWebApplicationContext;
+import org.springframework.web.util.WebUtils;
 
 import static org.junit.Assert.*;
 
 /**
  * @author Dave Syer
- * 
+ * @author Rossen Stoyanchev
  */
 public class RequestContextTests {
 
@@ -51,14 +52,14 @@ public class RequestContextTests {
 	}
 
 	@Test
-	public void testGetContextUrlString() throws Exception {
+	public void testGetContextUrl() throws Exception {
 		request.setContextPath("foo/");
 		RequestContext context = new RequestContext(request, response, servletContext, model);
 		assertEquals("foo/bar", context.getContextUrl("bar"));
 	}
 
 	@Test
-	public void testGetContextUrlStringMap() throws Exception {
+	public void testGetContextUrlWithMap() throws Exception {
 		request.setContextPath("foo/");
 		RequestContext context = new RequestContext(request, response, servletContext, model);
 		Map<String, Object> map = new HashMap<String, Object>();
@@ -66,7 +67,29 @@ public class RequestContextTests {
 		map.put("spam", "bucket");
 		assertEquals("foo/bar?spam=bucket", context.getContextUrl("{foo}?spam={spam}", map));
 	}
+	
+	@Test
+	public void testGetContextUrlWithMapEscaping() throws Exception {
+		request.setContextPath("foo/");
+		RequestContext context = new RequestContext(request, response, servletContext, model);
+		Map<String, Object> map = new HashMap<String, Object>();
+		map.put("foo", "bar baz");
+		map.put("spam", "&bucket=");
+		assertEquals("foo/bar%20baz?spam=%26bucket%3D", context.getContextUrl("{foo}?spam={spam}", map));
+	}
 
-	// TODO: test escaping of query params (not supported by UriTemplate but some features present in UriUtils).
+	@Test
+	public void testPathToServlet() throws Exception {
+		request.setContextPath("/app");
+		request.setServletPath("/servlet");
+		RequestContext context = new RequestContext(request, response, servletContext, model);
+		
+		assertEquals("/app/servlet", context.getPathToServlet());
+
+		request.setAttribute(WebUtils.FORWARD_CONTEXT_PATH_ATTRIBUTE, "/origApp");
+		request.setAttribute(WebUtils.FORWARD_SERVLET_PATH_ATTRIBUTE, "/origServlet");
+		
+		assertEquals("/origApp/origServlet", context.getPathToServlet());
+	}
 
 }

org.springframework.web/src/main/java/org/springframework/web/util/UrlPathHelper.java

@@ -280,6 +280,20 @@ public class UrlPathHelper {
 		return decodeRequestString(request, contextPath);
 	}
 
+	/**
+	 * Return the servlet path for the given request, detecting an include request
+	 * URL if called within a RequestDispatcher include.
+	 * @param request current HTTP request
+	 * @return the servlet path
+	 */
+	public String getOriginatingServletPath(HttpServletRequest request) {
+		String servletPath = (String) request.getAttribute(WebUtils.FORWARD_SERVLET_PATH_ATTRIBUTE);
+		if (servletPath == null) {
+			servletPath = request.getServletPath();
+		}
+		return servletPath;
+	}
+
 	/**
 	 * Return the query string part of the given request's URL. If this is a forwarded request,
 	 * correctly resolves to the query string of the original request.