doFilter not getting called

Question

Could you help to check why doFilter not getting called

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"    xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
<context-param>
<param-name>log4jConfigLocation</param-name>
<param-value>/WEB-INF/log4j.properties</param-value>
</context-param>
<listener>
    <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
</listener>
<filter>
<filter-name>roseFilter</filter-name>
<filter-class>net.paoding.rose.RoseFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>roseFilter</filter-name>
<url-pattern>/*</url-pattern>
<dispatcher>REQUEST</dispatcher>
<dispatcher>FORWARD</dispatcher>
<dispatcher>INCLUDE</dispatcher>
</filter-mapping>
</web-app>

class signature:

import org.springframework.web.filter.GenericFilterBean;
public class RoseFilter extends GenericFilterBean {

404 is returned while call http://localhost:8080/hello/world, I set the breakpoints at doFilter, it seems doFilter not called?(I tried tomcat 6.0.18, 6.0.29, jdk1.6)

Answer 1

The filter won't be invoked when:

1. The filter class is missing in the classpath and/or is not loadable or instantiable. You should however have noticed it in the server's startup logs. Solution is to be found based on the interpretation of the exceptions/errors found in the server logs.

2. There's another filter running before in the chain which isn't calling FilterChain#doFilter(), but rather RequestDispatcher#forward() or include() which caused the subsequent filters in the chain being completely skipped (when they do not listen on FORWARD or INCLUDE dispatchers; they by default only listens on REQUEST dispatcher). Solution is either to fix the wrong filter, or to add <dispatcher>FORWARD</dispatcher> etc accordingly, or to rearrange the filter declarations in web.xml so that your new filter comes before the another filter (you in turn only need to ensure that your new filter is using the FilterChain#doFilter() properly :) ).

3. The request URL is plain wrong. You used http://localhost:8080/hello/world. With a filter listening on /*, this means that the webapp context should be ROOT or at least /hello. Verify your webapp context. I'd just retry with an URL which points to a valid JSP/Servlet inside the same webapp which generates a non-404 response. Does the filter then get called as well?