HttpServletRequest Path Decoding

The documentation on HttpServletRequest is very poor, and this fills in a critical set of facts that you need to know to write a TomCat application.

The HttpServletRequest object will return the path to the current request with the following methods:

• getContextPath()
• getPathInfo()
• getPathTranslated()
• getQueryString()
• getRequestURI()
• getRequestURL()
• getServletPath()

Imagine you have a tomcat server installed at http://server:8080/

Imagine you install an application in this server at “myapp”

That application has a servlet mounted at “servlet1”

The user then makes a request:

http://server:port/myapp/servlet1/path/file.doc?q1=foo&q2=bar

Here is the map of how the various functions decode this:

I won’t repeat what the documentation says — things like “use getContextPath to get the context path” without any explanation of what “context” we are talking about or how much of that context is included.  A simple map like this helps show all the relationships.

 

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