by September 25th, 2011on
Web Applications are WAR files that include java code and JSP files with a web.xml deployment descriptor that are intended to implement dynamic web functionality (as opposed to static web functionality which uses HTML files).
A portal team typically uses this packaging technique for the following artifacts:
- Portal themes and skins
- web services
WebSphere Approach for Web Applications
The WebSphere Application server only understands EAR files. EAR files are collections of WAR and JAR files with an application.xml deployment descriptor. Developers that come from a Tomcat or JBoss (or similar J2EE application server) background may be accustomed to performing a hot deploy that simply involves them placing a WAR or EAR file in a specific directory. The WebSphere deployment is more involved because of clustering and vendor extensions that provide more robust enterprise features.
Now let’s assume you are creating a Spring web service implementation for your business logic. RAD automatically creates an associated EAR project for your WAR project when you choose dynamic web application during the project creation wizard. The EAR file is deployed on the WebSphere_Portal server instance of the WebSphere Application Server that includes your portal application.
The EAR file can be placed on the server using several techniques:
- administrative console (via the GUI)
- RAD menus that add project to a local server configuration (technique used by many developers during coding/debugging)
The wsadmin approach is the obvious choice for scripting releases. The administrative console approach is a multiple screen wizard that forces developers to choose values for many vendor extensions and security configurations that are typically beyond the domain knowledge of a component developer.
Maven Approach for Web Applications
A best practice of maven is to follow the one artifact for each pom.xml convention. We have already seen that WebSphere expects an EAR file that contains a WAR file for a typical web application. The solution for this problem is to create a multiple module maven project that serves as the parent for the WAR and EAR files that are required.
The deployment of the EAR file is handled by the was6 maven plugin from codehaus. This plugin will require that your Continuous Integration (CI) server handling the deployments has a WebSphere Application Server installation on the same machine. This is required because the was6 plugin is a wrapper for the wsadmin client (which includes an IBM component that handles the secured communications with a remote WAS instance). The configuration of the was6 maven plugin always requires specifying a -DwasHome property value that points to the root of the WAS server installation. I am not aware of any set of JAR files that implement this functionality (unlike the xmlaccess tool discussed in my WebSphere Portal and Maven post that can be implemented by including jars as dependencies of your custom plugin).
Next up I will discuss the file structure of the project used for my proposed solution for web applications.