added filter ordering comments (SPR-6594)

Author: jhoeller

org.springframework.web/src/main/java/org/springframework/web/filter/HiddenHttpMethodFilter.java

@@ -38,6 +38,11 @@
  * <p>The name of the request parameter defaults to <code>_method</code>, but can be
  * changed via the {@link #setMethodParam(String) methodParam} property.
  *
+ * <p><b>NOTE: This filter needs to run after multipart processing in case of a multipart
+ * POST request, due to its inherent need for checking a POST body parameter.</b>
+ * So typically, put a Spring {@link org.springframework.web.multipart.support.MultipartFilter}
+ * <i>before</i> this HiddenHttpMethodFilter in your <code>web.xml</code> filter chain.
+ *
  * @author Arjen Poutsma
  * @since 3.0
  */

org.springframework.web/src/main/java/org/springframework/web/multipart/support/MultipartFilter.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2006 the original author or authors.
+ * Copyright 2002-2010 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.
@@ -17,7 +17,6 @@
 package org.springframework.web.multipart.support;
 
 import java.io.IOException;
-
 import javax.servlet.FilterChain;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
@@ -46,9 +45,10 @@
  * for each call but rather return a reference to a pre-built instance.
  *
  * <p>Note: This filter is an <b>alternative</b> to using DispatcherServlet's
- * MultipartResolver support, for example for web applications with custom
- * web views that do not use Spring's web MVC. It should not be combined with
- * servlet-specific multipart resolution.
+ * MultipartResolver support, for example for web applications with custom web views
+ * which do not use Spring's web MVC, or for custom filters applied before a Spring MVC
+ * DispatcherServlet (e.g. {@link org.springframework.web.filter.HiddenHttpMethodFilter}).
+ * In any case, this filter should not be combined with servlet-specific multipart resolution.
  *
  * @author Juergen Hoeller
  * @since 08.10.2003
@@ -77,7 +77,7 @@ public void setMultipartResolverBeanName(String multipartResolverBeanName) {
 	 * root application context.
 	 */
 	protected String getMultipartResolverBeanName() {
-		return multipartResolverBeanName;
+		return this.multipartResolverBeanName;
 	}
 
 
@@ -143,9 +143,8 @@ protected MultipartResolver lookupMultipartResolver() {
 		if (logger.isDebugEnabled()) {
 			logger.debug("Using MultipartResolver '" + getMultipartResolverBeanName() + "' for MultipartFilter");
 		}
-		WebApplicationContext wac =
-				WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());
-		return (MultipartResolver) wac.getBean(getMultipartResolverBeanName(), MultipartResolver.class);
+		WebApplicationContext wac = WebApplicationContextUtils.getRequiredWebApplicationContext(getServletContext());
+		return wac.getBean(getMultipartResolverBeanName(), MultipartResolver.class);
 	}
 
 }