Chapter 2. Maven Guide
2.1. Learn about Maven
2.1.1. About the Maven Repository
Apache Maven is a distributed build automation tool used in Java application development to create, manage, and build software projects. Maven uses standard configuration files called Project Object Model, or POM, files to define projects and manage the build process. POMs describe the module and component dependencies, build order, and targets for the resulting project packaging and output using an XML file. This ensures that the project is built in a correct and uniform manner.
Maven achieves this by using a repository. A Maven repository stores Java libraries, plug-ins, and other build artifacts. The default public repository is the Maven 2 Central Repository, but repositories can be private and internal within a company with a goal to share common artifacts among development teams. Repositories are also available from third-parties. JBoss EAP 6 includes a Maven repository that contains many of the requirements that Java EE developers typically use to build applications on JBoss EAP 6. To configure your project to use this repository, see Section 2.3.1, “Configure the JBoss EAP Maven 6 Repository”.
Remote repositories are accessed using common protocols such as
http:// for a repository on an HTTP server or file:// for a repository on a file server.
For more information about Maven, see Welcome to Apache Maven.
For more information about Maven repositories, see Apache Maven Project - Introduction to Repositories.
For more information about Maven POM files, see the Apache Maven Project POM Reference and Section 2.1.2, “About the Maven POM File”.
2.1.2. About the Maven POM File
The Project Object Model, or POM, file is a configuration file used by Maven to build projects. It is an XML file that contains information about the project and how to build it, including the location of the source, test, and target directories, the project dependencies, plug-in repositories, and goals it can execute. It can also include additional details about the project including the version, description, developers, mailing list, license, and more. A
pom.xml file requires some configuration options and will default all others. See Section 2.1.3, “Minimum Requirements of a Maven POM File” for details.
The schema for the
pom.xml file can be found at http://maven.apache.org/maven-v4_0_0.xsd.
For more information about POM files, see the Apache Maven Project POM Reference.
2.1.3. Minimum Requirements of a Maven POM File
Minimum requirements
The minimum requirements of a pom.xml file are as follows:
- project root
- modelVersion
- groupId - the id of the project's group
- artifactId - the id of the artifact (project)
- version - the version of the artifact under the specified group
Sample pom.xml file
A basic pom.xml file might look like this:
<project> <modelVersion>4.0.0</modelVersion> <groupId>com.jboss.app</groupId> <artifactId>my-app</artifactId> <version>1</version> </project>
2.1.4. About the Maven Settings File
The Maven
settings.xml file contains user-specific configuration information for Maven. It contains information that should not be distributed with the pom.xml file, such as developer identity, proxy information, local repository location, and other settings specific to a user.
There are two locations where the
settings.xml can be found.
- In the Maven install
- The settings file can be found in the
M2_HOME/conf/directory. These settings are referred to asglobalsettings. The default Maven settings file is a template that can be copied and used as a starting point for the user settings file. - In the user's install
- The settings file can be found in the
USER_HOME/.m2/directory. If both the Maven and usersettings.xmlfiles exist, the contents are merged. Where there are overlaps, the user'ssettings.xmlfile takes precedence.
The following is an example of a Maven
settings.xml file:
<?xml version="1.0" encoding="UTF-8"?>
<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">
<profiles>
<!-- Configure the JBoss EAP Maven repository -->
<profile>
<id>jboss-eap-maven-repository</id>
<repositories>
<repository>
<id>jboss-eap</id>
<url>file:///path/to/repo/jboss-eap-6.3-maven-repository</url>
<releases>
<enabled>true</enabled>
</releases>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>jboss-eap-maven-plugin-repository</id>
<url>file:///path/to/repo/jboss-eap-6.3-maven-repository</url>
<releases>
<enabled>true</enabled>
</releases>
<snapshots>
<enabled>false</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
</profile>
</profiles>
<activeProfiles>
<!-- Optionally, make the repository active by default -->
<activeProfile>jboss-eap-maven-repository</activeProfile>
</activeProfiles>
</settings>
The schema for the
settings.xml file can be found at http://maven.apache.org/xsd/settings-1.0.0.xsd.
