Difference between revisions of "Jetty/Reference/override-web.xml"

Revision as of 13:35, 20 August 2010

Introduction

When you deploy a web application or WAR into different environments, most likely you will need to customize the webapp for compatibility with each environment. The challenge is to do so without changing the webapp itself. You can use a jetty.xml file for some of this work since jetty.xml is not part of the webapp. But there are some changes that jetty.xml cannot accomplish, for example, modifications to servlet init-params and context init-params. Using webdefault.xml is not an option because Jetty applies webdefault.xml to a web application "before" the application's own WEB-INF/web.xml, which means that it cannot override values inside the webapp's web.xml.

The solution is <<override-web.xml</tt>. It is a web.xml file that Jetty applies to a web application "after" the application's own WEB-INF/web.xml, which means that it can override values or add new elements. You define it per-webapp, using the web.xml syntax.

Using override-web.xml

You can specify the override-web.xml to use for an individual web application, in that webapp's jetty-web.xml.

<Configure class="org.eclipse.jetty.webapp.WebAppContext">
  ...
  <!-- Set up the path to the custom override descriptor, 
  relative to your $(jetty.home) directory or to the current directory -->
  <Set name="overrideDescriptor"><SystemProperty name="jetty.home" default="."/>/my/path/to/override-web.xml</Set>
  ...
</Configure>

The equivalent in code is:

import org.eclipse.jetty.webapp.WebAppContext;
 
    ...
 
    WebAppContext wac = new WebAppContext();
    ...
    //Set the path to the override descriptor, based on your $(jetty.home) directory
    wac.setOverrideDescriptor(System.getProperty("jetty.home")+"/my/path/to/override-web.xml");
    ...

Alternatively, use the classloader to get the path to the override descriptor as a resource.

Using the Jetty Maven Plugin

Use the <overrideDescriptor> tag as follows:

<project>
    ...
    <plugins>
        <plugin>
            ...
            <artifactId>jetty-maven-plugin</artifactId>
            <configuration>
                <webAppConfig>
                  ...
                  <overrideDescriptor>src/main/resources/override-web.xml</overrideDescriptor>
                </webAppConfig>
            </configuration>
        </plugin>
        ...
    </plugins>
    ...
</project>

Additional Resources

• web.xml Syntax Reference reference for web.xml files
• webdefault.xml web.xml-formatted file, applied before the webapp's web.xml