Question

I am using a some filter mapping for my project . The following filter pattens hit the filter

<filter-mapping>
       <filter-name>wygUserCheckFilter</filter-name>
       <url-pattern>*.jsp</url-pattern>
</filter-mapping>

<filter-mapping>
       <filter-name>wygUserCheckFilter</filter-name>
       <url-pattern>/myProject/MyDisplay.jsp</url-pattern>
</filter-mapping>

But the one below doesn’t hit the filter

<filter-mapping>
       <filter-name>wygUserCheckFilter</filter-name>
       <url-pattern>/myProject/*.jsp</url-pattern>
</filter-mapping>

Why is this so ?

Answer 1

Because * in the middle of the pattern matches only to the * character. Only matching url for /myProject/*.jsp-pattern is exactly same string. * does have special meaning only in the following cases (Servlet 2.4 Specification):

• A string beginning with a ‘/’ character and ending with a ‘/*’
  suffix is used for path mapping.
• A string beginning with a ‘*.’
  prefix is used as an extension mapping.
• A string containing only the
  ’/’ character indicates the “default” servlet of the application. In
  this case the servlet path is the request URI minus the con- text path
  and the path info is null.
• All other strings are used for exact
  matches only.