web applications - java: question on filter and servlet mapping -

i have web application following structure:

tomcat_home   |    webapps      |_myapp           |-html/           |-various directories           |-web-inf/           |-index.html 

the application has various servlets registered on various paths.
application can accessed via http://ip:port/myapp/
of courses causes index.html (in welcome list).
question is, how register filter access of root directory not subdirectories i.e. url-mapping not /* if place url-pattern / seems not work.
filter intercept request http://ip:port/myapp/ , not http://ip:port/myapp/path or http://ip:port/myapp/servlet/path.
additionally filter intercept request http://ip:port/myapp/index.html equivalent 1 aim.

thanks

you can test / , thing, otherwise let pass through. /* url pattern.

@override public void dofilter(servletrequest req,servletresponse res,filterchain chain)     throws ioexception,servletexception{      httpservletrequest request=(httpservletrequest)req;     string path=request.getservletpath();      if(path.equals("/") || path.equals("/index.html"){         // thing     }      chain.dofilter(req,res); }