You can get the response write or output stream using the or . Then you can very simply use the response object to write whatever data you want to.
As for your problem of
without going to Struts-Config
what I think you mean is not get forwarded to a particular JSP or Action (for ex. if you want to stream back an excel/pdf file) . What you need to do is return a object. This way it will not "Go to the Struts-Config"