Servlet Filter url-mapping /* is not working on 40

问题:

I'm using Resin Server & Apache 2.2 with virtual hosting. Here I'm facing a big challenge in calling a concrete filter. I'm having a generic Filter class to process all the incoming request.

Ex: www.example.com/hello this hello is not calling the below filter instead it throwing file not found error(404).

If "hello" is having a proper servlet mapping then the below filter is working.

Web.xml :

<filter>
  <filter-name>CorpFilter</filter-name>
  <filter-class>com.filter.CorpFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>CorpFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

Apache Log :

[Fri Jan 04 22:05:07 2013] [error] [client xxx.xxx.xxx.xxx] File does not exist: /home/xxxx/public_html/hello

Why the servlet filter is not being called and throwing 404 error? Servlet filter is initializing properly.

Thanks,

回答1:

Filters are by default dispatched on successful requests. They are by default not dispatched on erroneous requests. In order to dispatch them on erroneous requests as well, expand the filter mapping with the appropriate <dispatcher> elements:

<filter-mapping>
    <filter-name>CorpFilter</filter-name>
    <url-pattern>/*</url-pattern>
    <dispatcher>REQUEST</dispatcher>
    <dispatcher>ERROR</dispatcher>
</filter-mapping>

Note that when specifying custom dispatcher types and you'd like to keep the default REQUEST dispatcher, then you should be explicitly specifying it as well. Note that I also assume that the 404 is not handled by the web proxy (Apache HTTPD), but by the servlet container (Resin) itself, for obvious reasons.