Set - 4

Question 16 :

ActionServlet Configurations

Answer :

With the introduction of sub-applications, a more flexible way is introduced to configure each sub-application independently. Many of the configuration entries (e.g. resource bundle location, maximum upload file size, etc) that used to be defined in web.xml have now been moved to struts-config.xml. The original entries in web.xml are deprecated but will still be effective.


Question 17 :

Action.execute() and Action.getResources()

Answer :

In Struts 1.0, request handling logic is coded in Action.perform(); however, Action.perform() throws only IOException and SevletException. To facilitate the new declarative exception handling , the request handling method needs to throw Exception, the superclass of all the checked exceptions. Therefore, to both maintain backward compatibility and facilitate declarative exception handling, Action.perform() is now deprecated in favour of Action.execute().
You also have to be careful if you use DispatchAction in your existing applications. At the time of writing, the DispatchAction in Struts 1.1 beta has not yet been updated to use execute(). (A bug report has been filed in Struts' bug database.) Therefore, without modifying the DispatchAction class yourself, declarative exception handling will not work with DispatchAction subclasses.
In addition, Action.getResources() is now deprecated. Instead, you should call Action.getResources(HttpServletRequest) instead. This allows Struts to return to you the sub-application specific message resources. Otherwise, the message resources for the default sub-app will be used.


Question 18 :

Library Dependency

Answer :

Struts 1.1 now depends on a handful of libraries from other Jakarta subprojects (e.g. Commons-Logging, Commons-Collections, etc.). Some of these libraries may cause classloading conflicts in some servlet containers. So far, people have reported in the mailing list the classloading problem of commons-digester/jaxp1.1, and commons-logging causing deployment difficulties in Struts 1.1 applications running on Weblogic 6.0. (The problems have been corrected in Weblogic 6.1 and 7.0.)


Question 19 :

Resources under WEB-INF

Answer :

According to the Servlet specification, resources (e.g. JSP files) stored under WEB-INF are protected and cannot be accessed directly by the browsers. One design idiom for Struts 1.0 is to put all the JSP files under WEB-INF and front them by Actions so that clients cannot illegally access the JSPs. With the introduction of sub-application prefixes in Struts 1.1, mapping resources under WEB-INF gets complicated. Extra configuration steps utilizing the pagePattern and forwardPattern attributes of the element in struts-config.xml is required to inform Struts to construct the paths correctly. More specifically, you need to set these attributes to the pattern "/WEB-INF/$A$P".


Question 20 :

What is the Jakarta Struts Framework?

Answer :

Jakarta Struts is an open source implementation of MVC
(Model-View-Controller) pattern for the development of web based applications.
Jakarta Struts is a robust architecture and can be used for the development of applications of any size.
The "Struts framework" makes it easier to design scalable, reliable Web applications.