what are the following terms used in filter mapping?

<filter-mapping>
    <filter-name>richfaces</filter-name>
    <servlet-name>Faces Servlet</servlet-name>
    <dispatcher>REQUEST</dispatcher>
    <di开发者_如何学Pythonspatcher>FORWARD</dispatcher>
    <dispatcher>INCLUDE</dispatcher>
  </filter-mapping>

what is request,forward and include used for?

This is whether to invoke the filter when forward or include is used.

For example, if you have request.getRequestDispatcher("/bar.jsp").forward(req, resp), the filter will be invoked before the forwarded resource is processed.