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TOTD #101: Applying Servlet 3.0/Java EE 6 “web-fragment.xml” to Lift – Deploy on GlassFish v3

TOTD #100 explained how to deploy Lift framework applications on GlassFish v3. As explained in TOTD #91, Java EE 6 defines how the framework configuration deployment descriptor can be defined in “META-INF/web-fragment.xml” in the JAR file of the framework instead of mixing it with "WEB-INF/web.xml" which is intended for application deployment descriptor aspects.

This Tip Of The Day (TOTD) explains how to leverage ”web-fragment.xml” to deploy a Lift application on a Java EE 6 compliant container. The original "lift-*.jar" files are untouched and instead a new JAR file is included that contains only the framework configuration deployment descriptor.

The generated "web.xml" from TOTD #100 looks like:

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

<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>
<filter>
 <filter-name>LiftFilter</filter-name>
 <display-name>Lift Filter</display-name>
 <description>The Filter that intercepts lift calls</description>
 <filter-class>net.liftweb.http.LiftFilter</filter-class>
</filter>
 

<filter-mapping>
 <filter-name>LiftFilter</filter-name>
 <url-pattern>/*</url-pattern>
</filter-mapping>

</web-app>

The deployment descriptor defines a Servlet Filter (LiftFilter) that registers the Lift framework with the Web container. And then it defines a URL mapping to "/*". All of this information is required by the Lift framework for request dispatching. And so that makes this fragment suitable for "web-fragment.xml".

Here are simple steps to make this change:

1. Remove “src/main/webapp/WEB-INF/web.xml” because no application specific deployment descriptors are required.
2. Include “lift-web-fragment.jar” in the “WEB-INF/lib” of your application by adding the following fragment in your “pom.xml”:
   

   <dependencies>
           
   . . .
   
     <!– web-fragment –>
     <dependency>
       <groupId>org.glassfish.extras</groupId>
       <artifactId>lift-web-fragment</artifactId>
       <version>1.0</version>
       <scope>runtime</scope>
     </dependency>
   </dependencies>
   
   . . .
   
   <repositories>
     <repository>
       <id>maven2-repository.dev.java.net</id>
       <name>Java.net Repository for Maven</name>
       <url>http://download.java.net/maven/2/</url>
     </repository>
   </repositories>
   
   

   This file contains only “META-INF/web-fragment.xml” with the following content:

   <web-fragment>
    <filter>
    <filter-name>LiftFilter</filter-name>
    <display-name>Lift Filter</display-name>
    <description>The Filter that intercepts lift calls</description>
    <filter-class>net.liftweb.http.LiftFilter</filter-class>
    </filter>
    
   
    <filter-mapping>
    <filter-name>LiftFilter</filter-name>
    <url-pattern>/*</url-pattern>
    </filter-mapping>
   </web-fragment>
   
   

3. Create the WAR file without “web.xml” by editing “pom.xml” and adding the following fragment:
   

   <build>
      . . .
     <plugins>
       . . .
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-war-plugin</artifactId>
         <version>2.1-beta-1</version>
         <configuration>
           <failOnMissingWebXml>false</failOnMissingWebXml>
         </configuration>
       </plugin>
     </plugins>
   </build>
   

That's it, now now you can create a WAR file using “mvn package” and deploy this web application on GlassFish v3 latest promoted build (61 as of today) as explained in TOTD #100.

Technorati: totd glassfish v3 lift scala javaee6 servlet web-fragment

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