Question

I’m working with some old jsp apps and we are moving servers and so the urls have changed. The new url’s we were given have port numbers in them – http://example.com:8686/theapp

Now this line getServletContext().getInitParameter("contextName") returns example/ instead of example:8686/.

Is there a similar function or parameter that I can use so that the port number will be displayed in the url?

Answer 1

The getServletContext().getInitParameter() returns the value of a <context-param> of the given name which is hard specified in web.xml. This is not a dynamic value. You’d basically need to edit the <context-param> in question in order to provide the “right” value.

To dynamically get the port number of the current HTTP servlet request, you need to use HttpServletRequest#getServerPort() or HttpServletRequest#getLocalPort() instead, depending on which port number exactly you’d like to obtain: the one as specified in Host header, or the one which the server is actually using.

Please note that you’d normally use HttpServletRequest#getContextPath() to obtain the context name.