I have a lot of common areas in my web application design, for example footer, header sidebar, blocks...etc and going through all of the application JSP files to change somethin
Ideally yes, You need to create common files instead of redundant code because it might leads to many changes if u want to change a single thing. So try to use below code based on your requirement.
<%@ include is a static include,
Another solution: As you are using Spring framework try to use spring tiles search in google for more help for example SpringByExample