JSP include
A JSP page can include page
fragments from other files to form the complete response. There are two
include mechanisms: the include directive and the include
action.
include directive
The
include directive reports to the JSP compiler for including a complete file
into the current file. For
example the directive:
<%@ include file="filename.jsp"
%>
includes
the content of the specified file during the translation phase when the page
is converted to a servlet. In this phase, the actual main page and the
included file are simply merged.
include action
The include action allows you to insert files into the page being generated. For example the action:
<jsp:include
page=" relative URL"
flush="true" />
includes
the response generated by executing the specified page (a JSP page or
a servlet) during the request processing phase when the page is requested by
a user. That means, unlike the include
directive, which inserts the file at the time the JSP page is
translated into a servlet, this action inserts the file at the time the page
is requested.
Read more at: