edit a source file using maven at build time

I have one freemarker template file which loads all css and js files used in web app. But these multiple http requests causing increased page load time. I have asked to use only one js file combining all js files and minimize it and similarly for css.

The problem is USER doesn't want to make changes to templa开发者_如何学JAVAte file but instead asked me to make changes at runtime while building the WAR using maven.

Now is it possible to do so? Any comments from your experience.

Thanks, Hanumant.

There's a lot of tools for this. Take a look at YUI Compressor Maven Mojo, for instance.