Practically Groovy: Go Server-Side Up, with Groovy

By Andrew Glover
2005-05-05

Groovlets and GSPs

The prerequisites for working with Groovlets and GSPs are quite simple: You need a servlet container, and the latest and greatest version of Groovy. The beauty of these frameworks is that they map all URLs of a chosen pattern to a specific servlet via a web.xml file. Thus, the first step to setting up a Groovlets and GSP implementation is to define a Web application context and update its associated web.xml file. The file will include the specific servlet class definitions and their corresponding URL pattern.

I'll be using Apache Jakarta Tomcat, and I've created a context called groove. The directory layout is shown in Listing 3:

Listing 3. Directory listing of the groove context

./groove:

drwxrwxrwx+   3 aglover  users        0 Jan 19 12:14 WEB-INF

./WEB-INF:

-rwxrwxrwx+   1 aglover  users      906 Jan 16 14:37 web.xml

drwxrwxrwx+   2 aglover  users        0 Jan 19 17:12 lib

./WEB-INF/lib:

-rwxrwxrwx+   1 aglover  users   832173 Jan 16 14:28 groovy-1.0-beta-9.jar

-rwxrwxrwx+   1 aglover  users    26337 Jan 16 14:29 asm-1.5.2.jar

In the WEB-INF directory, I need to have a web.xml file with at least the elements shown in Listing 4:

Listing 4. A fully configured web.xml file

<?xml version="1.0" encoding="ISO-8859-1"?>

<web-app xmlns="http://java.sun.com/xml/ns/j2ee"

    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

    xsi:schemaLocation=

    "http://java.sun.com/xml/ns/j2ee

    http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"

    version="2.4">

    <servlet>

      <servlet-name>GroovyServlet</servlet-name>

      <servlet-class>groovy.servlet.GroovyServlet</servlet-class>

    </servlet>

    <servlet>

        <servlet-name>GroovyTemplate</servlet-name>

        <servlet-class>groovy.servlet.TemplateServlet</servlet-class>    

	</servlet>

    <servlet-mapping>

        <servlet-name>GroovyServlet</servlet-name>

        <url-pattern>*.groovy</url-pattern>

    </servlet-mapping>

    <servlet-mapping>

        <servlet-name>GroovyTemplate</servlet-name>

        <url-pattern>*.gsp</url-pattern>

    </servlet-mapping>

</web-app>

The definitions in the above web.xml file state that any request ending with .groovy (for example, http://localhost:8080/groove/hello.groovy) will be sent to the class groovy.servlet.GroovyServlet, while any request ending with .gsp will go to the class groovy.servlet.TemplateServlet.

My next step is to place two jars in the lib directory: the groovy distribution jar (in my case, groovy-1.0-beta-9.jar) and the corresponding asm jar (asm-1.5.2.jar for groovy beta-9).

Yep, it's that easy -- I'm ready to go.

Tutorial Pages:
» On-the-fly Server-Side Programming with Groovlets and GSPs
» Defining Functions in Scripts
» Groovlets and GSPs
» The Groovlet, Please
» A Diagnostic Groovlet
» What About Those GSPs?
» Refactor me this ...
» Conclusion
» Resources

First published by IBM DeveloperWorks

Related Tutorials:
» All about JAXP, Part 1
» Make Database Queries Without the Database
» Load List Values for Improved Efficiency
» 2 Ways To Implement Session Tracking
» A Simple Way to Read an XML File in Java
» Develop Aspect-Oriented Java Applications with Eclipse and AJDT