DZone
Thanks for visiting DZone today,
Edit Profile
  • Manage Email Subscriptions
  • How to Post to DZone
  • Article Submission Guidelines
Sign Out View Profile
  • Post an Article
  • Manage My Drafts
Over 2 million developers have joined DZone.
Log In / Join
Refcards Trend Reports
Events Video Library
Over 2 million developers have joined DZone. Join Today! Thanks for visiting DZone today,
Edit Profile Manage Email Subscriptions Moderation Admin Console How to Post to DZone Article Submission Guidelines
View Profile
Sign Out
Refcards
Trend Reports
Events
View Events Video Library
Zones
Culture and Methodologies Agile Career Development Methodologies Team Management
Data Engineering AI/ML Big Data Data Databases IoT
Software Design and Architecture Cloud Architecture Containers Integration Microservices Performance Security
Coding Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks
Culture and Methodologies
Agile Career Development Methodologies Team Management
Data Engineering
AI/ML Big Data Data Databases IoT
Software Design and Architecture
Cloud Architecture Containers Integration Microservices Performance Security
Coding
Frameworks Java JavaScript Languages Tools
Testing, Deployment, and Maintenance
Deployment DevOps and CI/CD Maintenance Monitoring and Observability Testing, Tools, and Frameworks

Integrating PostgreSQL Databases with ANF: Join this workshop to learn how to create a PostgreSQL server using Instaclustr’s managed service

Mobile Database Essentials: Assess data needs, storage requirements, and more when leveraging databases for cloud and edge applications.

Monitoring and Observability for LLMs: Datadog and Google Cloud discuss how to achieve optimal AI model performance.

Automated Testing: The latest on architecture, TDD, and the benefits of AI and low-code tools.

Trending

  • The Promise of Personal Data for Better Living
  • Setting up Request Rate Limiting With NGINX Ingress
  • OneStream Fast Data Extracts APIs
  • 12 Agile Principles for Successful Agile Development Practices

Getting the Most Out of the Maven settings.xml File

John Ferguson Smart user avatar by
John Ferguson Smart
·
Aug. 11, 09 · Interview
Like (0)
Save
Tweet
Share
18.42K Views

Join the DZone community and get the full member experience.

Join For Free

If you have ever used Maven to any extent, you will probably know about the settings.xml file. The settings.xml file contains environment-specific details such as proxy configurations, repositories, server usernames and passwords, and so on.

An example of what typically might go into a settings.xml file is shown here:

 

<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0
http://maven.apache.org/xsd/settings-1.0.0.xsd">
<localRepository>C:/maven/repository</localRepository>

<proxies>
<proxy>
<id>localproxy</id>
<active>true</active>
<protocol>http</protocol>
<host>proxy.acme.com</host>
<port>8080</port>
<username>scott</username>
<password>t0ps3cr3t</password>
<nonProxyHosts>*.acme.com</nonProxyHosts>
</proxy>
</proxies>
...
<servers>
<server>
<id>dbserver</id>
<username>scott</username>
<password>tiger</password>
</server>
</servers>
...
</settings>

The localRepository element, for example, is very useful if you are using a corporate environment where your home directory is sent over the network each morning when you log on. Placing the local repository in a different directory on your local hard disk will, in this case, save a lot of band width.

You can also define repositories, mirrors, profiles and properties your the settings.xml. I don't want to cover configuring these here, as it is fairly well documented elsewhere.

What is less well-known, or at least less frequently used, is the ability to use other data defined in the settings.xml file from within your pom.xml file. In fact, you can use any element of the settings.xml, though some are more useful than others.

One common, and easy, example is to use the localRepository variable. You might need to pass this variable to a script, or use it to refer to a particular JAR file in the repository (though there are usually more elegant solutions for that particular problem). You can use the localRepository property simply by referring to ${settings.localRepository}. For example, in the following code, we invoke an Ant script and pass it the local repository path in a property called "localRepository":

<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-antrun-plugin</artifactId>
<executions>
<execution>
<id>generate-stuff</id>
<phase>pre-comile</phase>
<goals>
<goal>run</goal>
</goals>
<configuration>
<tasks>
<ant target="generate">
<property name="localRepository" value="${settings.localRepository}"/>
</ant>
</tasks>
</configuration>
</execution>
</executions>
</plugin>

However, you can do much more interesting things, particularly when you also integrate Groovy into your build. For example, suppose that during the integration tests phase, we need to ensure that certain SQL scripts have been run on the database. We have a Groovy script called update-scripts.groovy that does just this, but it needs a username and password to be provided as command-line parameters. How could you run this script before the integration test phase, using the username and password that you defined in the settings.xml? Well, with a bit of Groovy magic, nothing is easier! The settings object is available to any Groovy scripting you integrate into your pom.xml, so you can simply use it like a normal object, as in the following example:

<plugin>
<groupId>org.codehaus.groovy.maven</groupId>
<artifactId>gmaven-plugin</artifactId>
<version>1.0-rc-5</version>
<executions>
<execution>
<id>process-db-scripts</id>
<phase>pre-integration-test</phase>
<goals>
<goal>execute</goal>
</goals>
<configuration>
<source>
def server = settings.servers.find{ it.id.equals('dbserver') }
"""groovy update-scripts.groovy -Ddb.username=${server.username}
-Ddb.password=${server.password}""".execute()
</source>
</configuration>
</execution>
</executions>
</plugin>

Easy as! In fact, once you know how to access not only the top-level variables, but also the collections within your settings.xml, the sky's the limit! Just be sure to remember to make sure that your builds stay portable - for example, don't define any properties in the settings.xml that don't have sensible default values in the pom.xml file.

From http://weblogs.java.net/blog/johnsmart

Opinions expressed by DZone contributors are their own.


Comments

Partner Resources

X

ABOUT US

  • About DZone
  • Send feedback
  • Careers
  • Sitemap

ADVERTISE

  • Advertise with DZone

CONTRIBUTE ON DZONE

  • Article Submission Guidelines
  • Become a Contributor
  • Visit the Writers' Zone

LEGAL

  • Terms of Service
  • Privacy Policy

CONTACT US

  • 3343 Perimeter Hill Drive
  • Suite 100
  • Nashville, TN 37211
  • support@dzone.com

Let's be friends: