Comparing Servlets and Portlets Part 2 : Using RequestDispatcher

In the last article we saw how we create a simple Servlet or a Portlet by implementing or extending appropriate interfaces and classes.

Lets continue to see what other differences are there.

RequestDispatcher

Unlike a Servlet where we can use either ServletRequest or ServletContext to get a RequestDispatcher object in a Portlet we can only use the PortletContext to do that. Just to refresh your memory RequestDispatcher can be used to forward the request to another Servlet or a JSP for further processing.

Comparing Servlets and Portlets Part 1 : Understanding the similarities and differences

People familiar with Servlet technology will be able to relate to Portlets. The concepts are more or less the same for both the technologies.

Lets do a quick walkthrough:

To start with the lets talk about their containers.

A container provides the environment in which the application can run. For running a servlet we will need a web application container like Tomcat.
On similar lines for a Portlet we need a Portlet Container. Most of the Portals today come with an inbuilt Portlet container to serve requests.

Article 1: My take on the current Portal Industry and various Job roles

In this article I will try to briefly sum up my experiences, so far, with the Portal and some of the confusions surrounding it.
Its a bigger topic and I might use some other posts to cover this. But here is a gentle introduction.

Around 5-6 years back when I started on my first Portal project the market was picking up and was a buzz with Portal solutions such as Liferay.
It was understandable because Portals allowed a company to make better websites and at the same time display aggregated content.
I don't see much difference even today except that the Portal market is growing and getting better each passing day. The only problem is
lack of support and good resources to meet the current market needs. So while Liferay has become stronger in all these years, thanks to
a ton of features and being open source, its not quite easy to find good resources who can help customize it for specific needs.

New Series of articles on Portal and Portlets

It has been quite a while since my last Post. During all this time I had the opportunity to work with several portal projects for various clients. In the next series of posts I will try to share my experiences so far, on various Portal and Portlet related topics.
I believe most of you must be using the new JSR 286 spec to create Portlets, so in the examples that I will present I will try to use this spec.
I will try to consolidate this Post with all the articles that I will publish for easy navigation. So it might be helpful to just  bookmark this Post.

List of articles:

Article 1: My take on the current Portal Industry and various Job roles

Comparing Servlets and Portlets Part 1 : Understanding the similarities and differences

Comparing Servlets and Portlets Part 2 : Using RequestDispatcher

Create a Struts Portlet using Liferay Plugin Sdk

There is an article available at Liferay Wiki to help you develop a Struts Based Portlet using there Plugin SDK, but chances are pretty high that the article alone wont suffice.

Here are a few problems you might face when you develop a Struts based Portlet.

1. You might get errors for ActionForward, ActionMapping and so on.
2. Your project will have compilation problems.

Here are a few simple steps to create a Struts Based portlet:

Struts and EJB application to JSR 168 Portlet

This has been quite a journey for me to convert an existing Struts2 application to a JSR 168 compliant Portlet which now runs using IBM WebSphere Server and Liferay Portal. The application also uses EJB and Hibernate.

Here are the steps that can probably help you in converting a Struts application to a Portlet.

Basics of a struts config file.

Any struts application has a struts config file which defines the mappings for any request that comes to the controller for processing. Understanding the concepts of this file can help you get a clear picture of Struts.
In this tutorial, we will just look at the normal facilities offered by the strutsconfig.xml.