Accessing Tomcat Context Path from Servlet

Question

In my Servlet I would like to access the root of the context so that I can do some JavaScript minifying.

It would be possible to do the minify as part of the install process but I would like to do it on Servlet startup to reduce the implementation cost.

Does anyone know of a method for getting the context directory so that I can load and write files to disk?

Answer 1

This should give you the real path that you can use to extract / edit files.

Javadoc Link

We're doing something similar in a context listener.

public class MyServlet extends HttpServlet {

    public void init(final ServletConfig config) {
        final String context = config.getServletContext().getRealPath("/");
        ...
    }

    ...
}

Answer 2

In my Servlet I would like to access the root of the context so that I can do some JavaScript minifying

You can also access the files in the WebContent by ServletContext#getResource(). So if your JS file is for example located at WebContent/js/file.js then you can use the following in your Servlet to get a File handle of it:

File file = new File(getServletContext().getResource("/js/file.js").getFile());

or to get an InputStream:

InputStream input = getServletContext().getResourceAsStream("/js/file.js");

That said, how often do you need to minify JS files? I have never seen the need for request-based minifying, it would only unnecessarily add much overhead. You probably want to do it only once during application's startup. If so, then using a Servlet for this is a bad idea. Better use ServletContextListener and do your thing on contextInitialized().