If you are using DisplayTag and need to have hidden variables like I do (I’m using Struts) then this is a nice way
…setting the ’s class and headerClass attributes to hidden, which is a CSS style whose display property is none. This is a simple but effective method for keeping data available in the request scope without having to display it to the user.
Code snip :
<display:column property=”id” title=”ID” class=”hidden” headerClass=”hidden” media=”html” />
Source : Creating Highly Functional Tables in JSP Using DisplayTag and JavaScript