- it will try to find the web application context root by matching the request url . it will match longest web application path .
- after finding the web application context root , it will try to match the remaining part of url with the available pattern in following order , any successful match will stop further matching
- it will try to find a exact match
- it will recursively match the longest path where path separator is '/'. if a path matching pattern is provided.
- if url contains some extension , it will try to match extension pattern.
- if no pattern is matched , it will go to default servlet , if defined by web application .
a path matching pattern is a url pattern which starts from / and end with '*' .
if a servlet is mapped with url pattern '/' then it is called the default servlet
if a servlet is mapped with empty string url pattern then it is mapped to context root of web application
HttpServletRequest Provide two methods for accessing url provided by user :
getServletPath() provides servlet path.
getPathInfo() provides excess path info if path matching pattern is used in finding the servlet.
now let's take examples to understand the process : <><><><><><><><><><><><><><><><><><><><><><><><> if a request is /abc it will match to ExactMatchServlet
here Servlet Path is /abc whereas path info is null
if a request is /abc/pqr , it will match to LongPathInfoServlet instead of PathInfoServlet because this path matched is longer .
here Servlet Path is /abc and path info will be /pqr .
if a request is /something/random , it will match to PathInfoServlet
here ServletPath is empty string whereas path info will be /something/random
if we change the PathInfoServlet's url mapping from /* to /something
and then , a request is made /something/random , then it will match to DefaultServlet .
here ServletPath is /something/random and path info is null .