Defining a Default Method within an Action for Struts 1

Question

Is there a way in struts 1 to define a default method within an action? Ie if if I had some action called "register" (with various methods associated with that method), could I then default to a certian method if the passed method is unknown?

To illustrate, say I have localhost:8000/register.do?method=processRegistration where processRegistration is a method within the register action. Now, if I were to instead navigate to a method that does not exist (ie localhost:8000/register.do?method=foobar) it would print a stacktrace error to the browser, giving a "NoSuchMethodException." My thinking would be to try and handle this case would be to define a default method that would be run in cases that trigger the exception. I'm not sure if my line of thinking is correct, but any help would be appreciated. Thanks!

Answer 1

Perhaps you need to create an error page to hide the stack trace? If yes, that's not related to struts. For example, define a custom error page in web.xml.

If you really want to do this I'm guessing you have something like this:

public class RegisterAction extends DispatchAction {

    public ActionForward processRegistrion(...) {
       ...
    }
}

DispatchAction throws the exception so extend DispatchAction and catch the exception, and send to a default method:

public abstract class MyDispatchAction extends DispatchAction {

    public ActionForward execute(...) {
        try {
            return super.execute(...);
        } catch (Exception e) {
            return defaultMethod(...);        
       }

    public abstract ActionForward defaultMethod(...);

}

and your class now extends 'MyDispacthAction and implements defaultMethod`:

public class RegisterAction extends MyDispatchAction {

    public ActionForward processRegistrion(...) {
       ...
    }

    public ActionForward defaultMethod(...) {
       ...
    }

}

But what would defaultMethod actually do?

Answer 2

If you are looking for another solution, you can override the unspecified method of DispatchAction.

public final class MyAction extends DispatchAction {

    @Override
    public ActionForward unspecified(final ActionMapping mapping, final ActionForm form, final HttpServletRequest request,
        final HttpServletResponse response) throws Exception {
    }
}

In my case, I have overrided the getParameter method too...in order to manage the case between parameter/method name (force a lowercase).