Deploying Liferay Maven Artifacts to a Repository

Deploying artifacts to a remote repository is important if you intend to share your Maven projects with others. First, you must have a remote repository that can hold deployed Maven artifacts. If you do not currently have a remote repository, see the Creating a Maven Repository tutorial to learn how you can set up a Nexus repository. Also make sure your [USER_HOME]/.m2/settings.xml file specifies your remote repository’s ID, user name, and password.

To deploy to a remote repository, your Liferay module should be packaged using Maven. Maven provides a packaging command that creates an artifact (JAR) that can be easily deployed to your remote repository. You’ll learn how to do this with a Liferay portlet module.

Once you’ve created a deployable artifact, you’ll configure your module project to communicate with your remote repository and use Maven’s deploy command to send it on its way. Once your module project resides on the remote repository, other developers can configure your remote repository in their projects and set dependencies in their project POMs to reference it.

To follow this tutorial, you’ll need a Liferay module built with Maven. For demonstration purposes, this tutorial uses the portlet.ds sample module project. To follow along with this module, download the portlet.ds ZIP.

1. Create a folder anywhere on your machine to serve as the parent folder for your Liferay modules. Unzip the portlet.ds module project into that folder.

2. Create a pom.xml file inside this folder. Copy the following logic into the parent POM:

   <?xml version="1.0" encoding="UTF-8"?>
   <project
       xmlns="http://maven.apache.org/POM/4.0.0"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
   >
   
       <modelVersion>4.0.0</modelVersion>
       <groupId>liferay.sample</groupId>
       <artifactId>liferay.sample.maven</artifactId>
       <version>1.0.0</version>
       <name>Liferay Maven Module Projects</name>
       <packaging>pom</packaging>
   
       <distributionManagement>
           <repository>
               <id>liferay-releases</id>
               <url>http://localhost:8081/nexus/content/repositories/liferay-releases</url>
           </repository>
       </distributionManagement>
   
       <modules>
           <module>portlet.ds</module>
       </modules>
   </project>
   

   The tags <modelVersion> through <packaging> are POM tags that are used frequently in parent POMs. Visit Maven’s POM Reference documentation for more information.

   The <distributionManagement> tag specifies the deployment repository for all module projects residing in the parent folder. You should include the repository’s ID and URL. The above distributionManagement declaration is configured for the Liferay Nexus repository created in the Creating a Maven Repository tutorial. That tutorial also created the [USER_HOME]/.m2/settings.xml, which specified the remote repository’s ID, user name, and password. Both the parent POM and settings.xml file’s repository declarations are required to deploy your modules to that remote repository.

   Finally, you must list the modules residing in the parent folder that you want deployed using the <modules> tag. The portlet.ds module is specified within that tag.

3. Open the portlet.ds module’s pom.xml file. If you did not download the portlet.ds module project Zip, you can reference its POM below.

   <project
       xmlns="http://maven.apache.org/POM/4.0.0"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
   >
   
       <modelVersion>4.0.0</modelVersion>
       <artifactId>portlet.ds</artifactId>
       <version>1.0.0</version>
       <packaging>jar</packaging>
   
       <parent>
           <groupId>liferay.sample</groupId>
           <artifactId>liferay.sample.maven</artifactId>
           <version>1.0.0</version>
           <relativePath>../pom.xml</relativePath>
       </parent>
   
       <dependencies>
           <dependency>
               <groupId>javax.portlet</groupId>
               <artifactId>portlet-api</artifactId>
               <version>2.0</version>
               <scope>provided</scope>
           </dependency>
           <dependency>
               <groupId>org.osgi</groupId>
               <artifactId>org.osgi.service.component.annotations</artifactId>
               <version>1.3.0</version>
               <scope>provided</scope>
           </dependency>
       </dependencies>
   </project>
   

   The portlet.ds module’s POM specifies its own attributes first, followed by the parent POM’s attributes. Declaring the <parent> tag like above links the portlet.ds module to its parent POM, which is necessary to deploy to the remote repository. Then the module’s dependencies are listed. These dependencies are downloaded from the Central Repository and installed to your local .m2 repository when you package the portlet.ds module.

4. Now that you’ve configured your parent POM and module POM, package your Maven project. Navigate to your module project (e.g., project.ds) in your command prompt and run the Maven package command:

   mvn package
   

   This downloads and installs all your module’s dependencies and packages the project into a JAR file. Navigate to your module project’s generated build folder (e.g., /target). You’ll notice there is a newly generated JAR file. This is the artifact you’ll deploy to your Nexus repository.

5. Run Maven’s deploy command to deploy your module project’s artifact to your configured remote repository.

   mvn deploy
   

   Your console shows output from the artifact being deployed into your repository server.

To verify that your artifact is deployed, navigate to the Repositories page of your Nexus server and select your repository. A window appears below showing the Liferay artifact now deployed to your repository.

Figure 1: Your repository server now provides access to your Liferay Maven artifacts.

Awesome! You can now share your Liferay module projects with anyone by deploying them as artifacts to a remote repository!