Servlet init parameters common to more servlets

Question

Hi all,
I have a set of servlets using each one some init parameters.
Some of these parameters are common to a certain number of servlets.
Does exist a place where to put this init-parameter, avoiding to repeat these values
in all the definions of the servlets in the web xml file (I am using Tomcat 4.x) ?
thanks in advance,
Andrea

Answer 1

instead of adding a init-param to the servlet tag you also might add a context-param tag to the web-app.
please see the web-app DTD file to see the exact structure (i think it's named context-param and the child-elements are similar to those of init-param - but sorry - i'm not 100% sure).
inside the servlet you could then do something like the following:
// this = e.g. a HttpServlet
String param = this.getServletConfig().getInitParameter("your_param");
if(param == null) {
  param = this.getServletContext().getInitParameter("your_param");
  if(param == null) {
    throw new ServletException("Missing parameter");
}result:
servlet searches the servlet specific init parameters
if the parameter could be found it will be used (servlet param "overwrites" global param)
else the servlet searches the webapp specific init parameter
if the parameter could be found it will be used
else the servlet throws an exception