I’m currently developing some Java Servlets and one of the tasks is to create images dynamically. But where to store them accessible for users?

If you want to show the user for example a graph of some stuff that changes frequently you need to generate the image dynamically. The rendering of the graphic is one thing, but where to store the picture so that the visitor can access it from the web?

There were many options to try, and I found that getServletContext().getRealPath (".") from ServletRequest was the result I’ve been looking for. So to spare you the tests I’ll provide the different options (download):

Let’s assume your webapps-directory is /var/lib/tomcat6/webapps/ , your servlet context is project and the user asks for the servlet test the output probably looks like:

new File (".").getAbsolutePath () => /var/lib/tomcat6/.
request.getPathInfo () => null
request.getPathTranslated () => null
request.getContextPath () => /project
request.getRealPath (request.getServletPath ()) => /var/lib/tomcat6/webapps/project/test
request.getServletPath () => /test
getServletContext ().getContextPath () => /project
getServletContext ().getRealPath (".") => /var/lib/tomcat6/webapps/project/.

That’s it for the moment ;-)

Download: Java: ServletTest.java (Please take a look at the man-page. Browse bugs and feature requests.)

Martin Scharm

stuff. just for the records.


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