Create a controller and a generator to create your sitemap

RenderSitemap.java

package helpers;

public class RenderSitemap extends RenderSitemapXml {
	public RenderSitemap(List<User> users) {
		super(getDocument(users));
	}

	private static Document getDocument(List<User> users) {

		Document doc = createSiteMapDocument();
		Element root = doc.getDocumentElement();
		
		addAnnotatedActions(doc);
		
		for(User u : users) {
			Map<String, Object> args = new HashMap<String, Object>();
			args.put("userName", u.userName);
			String loc = Router.getFullUrl("Application.showUser", args);
			root.appendChild(createUrl(doc, loc, "weekly", 0.7));
		}

		return doc;
	}

}

Sitemap.java

package controllers;

public class Sitemap extends Controller {
    public static void generate() {
        List<User> users = User.findAll();
        throw new RenderSitemap(users);
    }
}