Eliminate conditions in JSP

I have a Servlet that checks for information and if there is an issue
it forwards the message to presentation page (JSP). Now I want to stop
using conditions in scriptlets in the JSP. Please advise how I can do
it in this situation in my Tomcat 4.1.27 container:

Servlet that forwards to JSP:

....
String gotopage = "";
if(mydata == 1)
{
     gotopage = /"pager.jsp?mymessage=err";
}
else if(mydata == 34
{
   gotopage = /"pager.jsp?mymessage=duper";
}
else
{
    gotopage = /"pager.jsp?mymessage=proc";
}

RequestDispatcher dispatcher =
  getServletContext().getRequestDispatcher(gotopage);
dispatcher.forward(request, response);
....

JSP

<%
String mymessage = request.getParameter("mymessage")

if(mymessage.equals("err"))
{
     out.println("Error on the page");
}
else if(mymessage.equals("dup"))
{
     out.println("Duplicate issue.");
}
else if(mymessage.equals("proc"))
{
     out.println("Process message issue");
}
%>

I was thinking maybe a bean or regular Java class to handle this but
not sure how. Here would be my method in a Java class:

public void getMessage(String msg)
{
     if(msg.equals("err"))
     {
         out.println("Error on the page");
     }
     ...

}

Then I would put the method in a bean or what in JSP?
The Servlet would stay the same?