Specifying Automatically Included Files
If a lot of tag libraries are used for an application, or a set of
pages need the same page attribute values to be set,
it’s easier to maintain the application if all the
common declarations are placed in one file that is then included in
all JSP pages. You can do so with the include
directive, but then you run the risk of forgetting to include the
file in a page. JSP 2.0 introduces a better solution: automatic
includes.
You can use one or more <include-prelude>
elements to include files at the beginning of all JSP pages that
match the JSP property group URL pattern, and one or more
<include-coda>
elements to include files at
the end of the JSP files. As opposed to all other configuration
properties, you can even use multiple JSP property groups to define
these two elements; the include elements from all groups that match
the request URL are applied:
<web-app ...> ... <jsp-config> <jsp-property-group> <url-pattern>*.jsp</url-pattern> <include-prelude>/WEB-INF/segments/taglibDecl.jspf</include-prelude> <include-prelude>/WEB-INF/segments/errorPageDecl.jspf</include-prelude> <include-coda>/WEB-INF/segments/copyright.jspf</include-coda> </jsp-property-grop> <jsp-property-group> <url-pattern>/main/*</url-pattern> <include-prelude>/WEB-INF/segments/noSessionDecl.jspf</include-prelude> </jsp-property-group> </jsp-config> ... </web-app>
In this example, I use one group for the *.jsp
pattern that include files with common tag library and error page declarations ...
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