Re: how to implement a front controller?

are you looking for a MVC (Model-View-Controller)? See http://jakarta.apache.org/struts/index.html

Maciek Zywno wrote:

hello

I wanted to write a simple front controller.
As for now it is to do nothing else than just take a look inside a request,
check what page a client wants to see and just forward a request to an appropriate
page. Is it possible?

In my web.xml I put mapping for all requests
to be checked by my front controller:

<servlet>

<servlet-name>FrontController</servlet-name>

<servlet-class>frontController</servlet-class>

</servlet>

<servlet-mapping>

<servlet-name>FrontController</servlet-name>

<url-pattern>/*</url-pattern>

</servlet-mapping>

in doProcess:

String urlTarget = request.getgetPathInfo();

RequestDispatcher dispatcher = getServletContext().getRequestDispatcher(urlTarget);

dispatcher.forward( request, response );

when I try to visit any page in my webapp
I get the error

java.lang.ClassCastException
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:243)
.....

at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2344)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:566)
at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:170)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:170)
at org.apache.catalina.core.StandardPipeline.invokeNext(StandardPipeline.java:564)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:462)
....

Do you have any idea of what is wrong with my piece of code?

thanks in advance

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