When will Container initialize multiple JSP/Servlet Objects?

Question

I have a JSP with a layout. it means the JSP has menu on the left and header on the top. now for every action the center part of the JSP should change. Is this possible?

I mean for every different action a different JSP should be included in the center of the layout JSP. If this is possible it will be of so much help. kindly help? if possible is there a solution without tiles?

Answer 1

If we have multiple servlet and servlet-mapping elements in deployment descriptor for a single servlet or JSP page, then container will initialize an object for each of the element and all of these instances will have their own ServletConfig object and init params.

For example, if we configure a single JSP page in web.xml like below.

<servlet>
  <servlet-name>Test</servlet-name>
  <jsp-file>/WEB-INF/test.jsp</jsp-file>
  <init-param>
    <param-name>test</param-name>
    <param-value>Test Value</param-value>
  </init-param>
</servlet>

<servlet-mapping>
  <servlet-name>Test</servlet-name>
  <url-pattern>/Test.do</url-pattern>
</servlet-mapping>

<servlet>
  <servlet-name>Test1</servlet-name>
  <jsp-file>/WEB-INF/test.jsp</jsp-file>
</servlet>

<servlet-mapping>
  <servlet-name>Test1</servlet-name>
  <url-pattern>/Test1.do</url-pattern>
</servlet-mapping>

Then if we can access same JSP page with both the URI pattern and both will have their own init params values.