Request Path Elements
The request path that leads to a servlet servicing a request is composed of many important sections. The following elements are obtained from the request URI path and exposed via the request object:
=> Context Path: The path prefix associated with the ServletContext that this servlet is a part of. If this context is the “default” context rooted at the base of the Web server’s URL name space, this path will be an empty string. Otherwise, if the context is not rooted at the root of the server’s name space, the path starts with a’/’ character but does not end with a’/’ character.
=> Servlet Path: The path section that directly corresponds to the mapping which activated this request. This path starts with a’/’ character except in the case where the request is matched with the ‘/*’ pattern, in which case it is an empty string.
=> PathInfo: The part of the request path that is not part of the Context Path or the Servlet Path. It is either null if there is no extra path, or is a string with a leading ‘/’.
The following methods exist in the HttpServletRequest interface to access this information:
=> getContextPath
=> getServletPath
=> getPathInfo
It is important to note that, except for URL encoding differences between the request URI and the path parts, the following equation is always true:
requestURI = contextPath + servletPath + pathInfo
To give a few examples to clarify the above points, consider the following:
Table 1: Example Context Set Up
Context Path /catalog
Servlet Mapping Pattern: /lawn/*
Servlet: LawnServlet
Servlet Mapping Pattern: /garden/*
Servlet: GardenServlet
Servlet Mapping Pattern: *.jsp
Servlet: JSPServlet
The following behavior is observed:
Table 2: Observed Path Element Behavior
Request Path Path Elements
/catalog/lawn/index.html ContextPath: /catalog
ServletPath: /lawn
PathInfo: /index.html
/catalog/garden/implements/ ContextPath: /catalog
ServletPath: /garden
PathInfo: /implements/
/catalog/help/feedback.jsp ContextPath: /catalog
ServletPath: /help/feedback.jsp
PathInfo: null
=> Context Path: The path prefix associated with the ServletContext that this servlet is a part of. If this context is the “default” context rooted at the base of the Web server’s URL name space, this path will be an empty string. Otherwise, if the context is not rooted at the root of the server’s name space, the path starts with a’/’ character but does not end with a’/’ character.
=> Servlet Path: The path section that directly corresponds to the mapping which activated this request. This path starts with a’/’ character except in the case where the request is matched with the ‘/*’ pattern, in which case it is an empty string.
=> PathInfo: The part of the request path that is not part of the Context Path or the Servlet Path. It is either null if there is no extra path, or is a string with a leading ‘/’.
The following methods exist in the HttpServletRequest interface to access this information:
=> getContextPath
=> getServletPath
=> getPathInfo
It is important to note that, except for URL encoding differences between the request URI and the path parts, the following equation is always true:
requestURI = contextPath + servletPath + pathInfo
To give a few examples to clarify the above points, consider the following:
Table 1: Example Context Set Up
Context Path /catalog
Servlet Mapping Pattern: /lawn/*
Servlet: LawnServlet
Servlet Mapping Pattern: /garden/*
Servlet: GardenServlet
Servlet Mapping Pattern: *.jsp
Servlet: JSPServlet
The following behavior is observed:
Table 2: Observed Path Element Behavior
Request Path Path Elements
/catalog/lawn/index.html ContextPath: /catalog
ServletPath: /lawn
PathInfo: /index.html
/catalog/garden/implements/ ContextPath: /catalog
ServletPath: /garden
PathInfo: /implements/
/catalog/help/feedback.jsp ContextPath: /catalog
ServletPath: /help/feedback.jsp
PathInfo: null
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