You pass init parameter to a JSP the same as a servlet, using the web.xml deployment descriptor. The key is using the <jsp-file> element instead of <servlet-class>:
<servlet>
<servlet-name>foo</servlet-name>
<jsp-file>myFile.jsp</jsp-file>
<init-param>
<param-name>flavor</param-name>
<param-value>vanilla</param-value>
</init-param>
</servlet>
Note, however, that you need to call the JSP by its servlet name, which would be %WEBAPPNAME%/servlet/foo, in the case above. If you don't, the servlet engine will not be aware that you are using the <servlet> element with its init parameters.
You can additionally supply a servlet mapping if you still want to use a "jsp" name:
<servlet-mapping>
<servlet-name>foo</servlet-name>
<url-pattern>myFile.jsp</url-pattern>
</servlet-mapping>
If you've never read the JSP specification or the DTD, it can be of great help to you.
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Phil Hanna
Sun Certified Programmer for the Java 2 Platform
Author of :
JSP: The Complete Reference Instant Java Servlets