With the release of Tomcat 7, Java web application developers have an alternative to GlassFish 3 for testing and running web applications that use the new Servlet 3.0 specification that is part of Jave EE 6. Oracle provides a good online tutorial for learning about Java EE 6 and Servlet 3.0. However, the tutorial's example applications are geared toward either using NetBeans or Ant and the GlassFish 3 server. Since I use Maven and Tomcat, I wanted to try out the Servlet 3.0 example application in Tomcat 7. This article provides a Maven version of the mood example application that is part of the Servlet 3 tutorial. The "mavenized" version of the tutorial's mood project can be easily packaged and deployed to the Tomcat 7 Servlet/JSP container.
Get Tomcat 7
Visit http://tomcat.apache.org to get the latest version of Tomcat 7. The documentation provides instructions on how to install Tomcat on various operating systems.
Tomcat 7 provides support for the Servlet 3.0 and JavaServer Pages 2.2 specifications. The Tomcat 7 documentation includes links to the APIs for Servlet 3.0 and JSP 2.2.
Servlet 3.0 Tutorial
Visit Oracle's Servlet 3.0 tutorial, where you can learn about what's new in 3.0. As part of that tutorial, Oracle provides an example application named mood. As best I can tell, Oracle wants you to first get the GlassFish 3 server and then use its update tool to get the example applications. You can then open the examples in NetBeans and run them in GlassFish (there is also an Ant build script).
That's quite a bit of work just to test running a Serlvet 3.0 example, so with the release of Tomcat 7, I thought I'd create a Maven version of the mood project that could be packaged into a war file and deployed to Tomcat 7.
Mood Servlet 3.0 Example Application
The mood Servlet 3.0 example application is copyrighted by Oracle with a license that allows redistribution (see http://developer.sun.com/berkeley_license.html). So I created a Maven version of the mood project that can be built using Maven and easily imported into other Java IDEs such as Eclipse. You can download the mood example project--maven version.
After downloading mood.zip, unzip it and import it into any Java IDE that supports Maven.
If you examine the pom.xml you'll see an artifact dependency for the javax.servlet-3.0.jar. Though this Jar is provided by Tomcat 7, I needed it in my project's class path for compiling the source code (note the dependency's scope is "provided"). The javax.servlet-3.0.jar is not available in the public Maven central repository so I added a repository node to pom.xml for the GlassFish maven repository where that jar is available.
How To Configure Maven To Handle A Missing web.xml
The Servlet 3.0 specification makes web.xml optional since much of the configuration that used to be in web.xml can now be handled via annotations. However, Maven's (I'm using 3.0.2 version) package phase will error if there is no web.xml file found under WEB-INF. To avoid this error include the following plugin in the build section of your project's pom.xml
Build, Deploy, and Run The Mood Servlet 3.0 Example Application
After unzipping the downloaded mood example project, open a terminal (command) window and navigate to the project's root folder (where pom.xml is). Enter mvn -e clean and then mvn -e package to create the war file.
Change to the target folder and copy the mood.war file to your Tomcat 7 installation webapps folder. Startup Tomcat 7. Then open a web browser and go to http://localhost:8080/mood/greeting.
If you don't get a web page with an image of Duke and a message about Duke's mood, then open console.out in your Tomcat 7 installation logs folder and review it for any error messages that might indicate the reason.
The release of Apache's Tomcat 7 Servlet/JSP container gives Java web developers an alternative to using GlassFish 3 for testing/running web applications that use Servlet 3.0. If you're used to using Maven and Tomcat together in your Java web development then understanding how to "Mavenize" the Servlet 3.0 examples provided by Oracle might be helpful.
One note--if you want to explore using JavaServer Faces (JSF) 2.0 with Tomcat 7, you'll need to copy the JSF 2 jar files into your Tomcat 7 installation lib folder. Unlike GlassFish 3, Tomcat 7 doesn't come with built-in support for JSF 2.