Hi suzy,
There is nothing stopping you from using GWT in your Struts application. One point of conflict I could think of is controlling application flow, as Struts does seem to prescribe a Web 1.0 style navigation flow, however you can definitely add GWT components to your existing Struts pages to enhance them.
In your case, it seems like you simply want to use GWT to display data within your Struts page. You can do this by simply coding up your GWT component (both the widget layout and style itself along with the logic to grab the data to be displayed from the page), and binding the component to an element in your Struts page. You can read more details about how to bind the component to your Struts page in the documentation linked below.
Organizing Projects - HTML Host Pages (same concept applies to a Struts page):
-Sumit Chandel