Allow RedirectAttributes on ExceptionHandlers

Prior to this commit, `@ExceptionHandler` methods could not be injected
with `RedirectAttributes` arguments. This would make it impossible to
handle an error by redirecting to another view and add flashmap
attributes, to be included in the model when the next view is called.

Here is an example:

```
@ExceptionHandler(MyException.class)
public String handleException(MyException ex, RedirectAttributes
    redirectAttributes) {

  redirectAttributes.addFlashAttribute("errorMessage",
      "This is an error message");
  return "redirect:/";
}
```

This commit adds a new `RedirectAttributesMethodArgumentResolver`
instance in the list of pre-configured `HandlerMethodArgumentResolver`
in `ExceptionHandlerExceptionResolver`.

Issue: SPR-14651

spring-webmvc/src/test/java/org/springframework/web/servlet/mvc/method/annotation/ExceptionHandlerExceptionResolverTests.java

@@ -42,7 +42,10 @@ import org.springframework.web.method.HandlerMethod;
 import org.springframework.web.method.annotation.ModelMethodProcessor;
 import org.springframework.web.method.support.HandlerMethodArgumentResolver;
 import org.springframework.web.method.support.HandlerMethodReturnValueHandler;
+import org.springframework.web.servlet.DispatcherServlet;
+import org.springframework.web.servlet.FlashMap;
 import org.springframework.web.servlet.ModelAndView;
+import org.springframework.web.servlet.mvc.support.RedirectAttributes;
 import org.springframework.web.util.NestedServletException;
 
 import static org.junit.Assert.*;
@@ -53,6 +56,7 @@ import static org.junit.Assert.*;
  * @author Rossen Stoyanchev
  * @author Arjen Poutsma
  * @author Kazuki Shimizu
+ * @author Brian Clozel
  * @since 3.1
  */
 @SuppressWarnings("unused")
@@ -82,6 +86,7 @@ public class ExceptionHandlerExceptionResolverTests {
 		this.resolver = new ExceptionHandlerExceptionResolver();
 		this.resolver.setWarnLogCategory(this.resolver.getClass().getName());
 		this.request = new MockHttpServletRequest("GET", "/");
+		this.request.setAttribute(DispatcherServlet.OUTPUT_FLASH_MAP_ATTRIBUTE, new FlashMap());
 		this.response = new MockHttpServletResponse();
 	}
 
@@ -192,6 +197,20 @@ public class ExceptionHandlerExceptionResolverTests {
 		assertEquals("IllegalArgumentException", mav.getModelMap().get("exceptionClassName"));
 	}
 
+	@Test  // SPR-14651
+	public void resolveRedirectAttributesAtArgument() throws Exception {
+		IllegalArgumentException ex = new IllegalArgumentException();
+		HandlerMethod handlerMethod = new HandlerMethod(new RedirectAttributesController(), "handle");
+		this.resolver.afterPropertiesSet();
+		ModelAndView mav = this.resolver.resolveException(this.request, this.response, handlerMethod, ex);
+
+		assertNotNull(mav);
+		assertEquals("redirect:/", mav.getViewName());
+		FlashMap flashMap = (FlashMap) this.request.getAttribute(DispatcherServlet.OUTPUT_FLASH_MAP_ATTRIBUTE);
+		assertNotNull("output FlashMap should exist", flashMap);
+		assertEquals("IllegalArgumentException", flashMap.get("exceptionClassName"));
+	}
+
 	@Test
 	public void resolveExceptionGlobalHandler() throws Exception {
 		AnnotationConfigApplicationContext cxt = new AnnotationConfigApplicationContext(MyConfig.class);
@@ -364,6 +383,18 @@ public class ExceptionHandlerExceptionResolverTests {
 		}
 	}
 
+	@Controller
+	static class RedirectAttributesController {
+
+		public void handle() {}
+
+		@ExceptionHandler
+		public String handleException(Exception ex, RedirectAttributes redirectAttributes) {
+			redirectAttributes.addFlashAttribute("exceptionClassName", ClassUtils.getShortName(ex.getClass()));
+			return "redirect:/";
+		}
+	}
+
 
 	@RestControllerAdvice
 	@Order(1)