This document provides examples and explanations of using Maven for building Java projects. It begins with installing Maven and describing its core concepts like the project object model (POM), plugins, goals, lifecycles and dependency management. It then walks through two examples: a simple project built and run with Maven commands, and using Maven to optimize a more complex project structure. The document also explains how to set up a Maven repository for dependency storage and integration with Jenkins for continuous integration builds.

1. Learning Maven by
example
Hsi-Kai Wang

2. Outline
• Introduction to Maven
• Example 1 - simple case
– build jar with command
– build jar with maven
• Example 2 - complex case
– optimize POM
• Maven Repository
• Maven Project on Jenkins

3. Build Jar Flow
submit sync
send email
deploy
dependency

4. Introduction to Maven
• What is maven
– A more formal definition of Apache Maven: Maven is a
project management tool which encompasses a project
object model, a set of standards, a project lifecycle, a
dependency management system, and logic for executing
plugin goals at defined phases in a lifecycle.
• Convention over Configuration
– Maven concept is "Convention over Configuration". Maven
provides default values for the project's configuration.
Systems, libraries, and frameworks should assume
reasonable defaults. Without requiring unnecessary
configuration, systems should "just work"
Ref: apche Maven

5. Installation
• # install maven
centos:~ # wget
http://ftp.tc.edu.tw/pub/Apache/maven/maven-
3/3.3.9/binaries/apache-maven-3.3.9-bin.tar.gz
centos:~ # tar zxf apache-maven-3.3.9-bin.tar.gz -C
/opt
centos:~ # ln -s /opt/apache-maven-3.3.9 /opt/apache-
maven
• # setup environment variable
centos:~ # export MAVEN_HOME=/opt/apache-maven
centos:~ # export PATH=$PATH:$MAVEN_HOME/bin
centos:~ # echo $JAVA_HOME
centos:~ # mvn -v
• # other maven options
centos:~ # export MAVEN_OPTS="-Xms512m"

6. Example 1 - code & config
mypackage/Hello.java
log4j.properties
mypackage/HelloTest.java

7. Example 1 – build, run & test
• # compile
centos:~ # javac -cp log4j-1.2.12.jar
mypackage/Hello.java
centos:~ # javac -cp ~/junit-4.10.jar:mypackage.jar
mypackage/HelloTest.java
• # package (create jar)
centos:~ # jar cf mypackage.jar mypackage
• # run
centos:~ # java -cp log4j-1.2.12.jar:mypackage.jar -
Dlog4j.configuration=file:///root/log4j.properties
centos:~ # java -cp ~/junit-4.10.jar:mypackage.jar
org.junit.runner.JUnitCore mypackage/HelloTest

8. Example 1 - maven folder
structureproject folder
test case folder
application folder

9. Example 1 - pom.xml
jar cf mypackage.jar mypackage
javac -cp log4j-1.2.12.jar mypackage/Hello.java
java -cp log4j-1.2.12.jar mypackage

10. Example 1 - maven command
• # help
centos:~/project # mvn help:describe -Dplugin=clean [-
Dfull]
• # compile
centos:~/project # mvn clean compile
• # run test case
centos:~/project # mvn clean test [-
Dmaven.test.failure.ignore=true]
• # package
centos:~/project # mvn clean package
• # install module
centos:~/project # mvn clean install [-DskipTests]
• # run
centos:~/project # mvn exec:java [-
Dexec.mainClass=mypackage.Hello]

11. Example 1 - mvn compile &
package

12. Maven Core Concept
• Coordinates
• Plugins and Goals
• Lifecycle
• Repositories
• Dependency Management
• Site Generation and Reporting

13. Coordinates
coordinates
description

14. Plugin and Goal
• Maven is - at its heart - a plugin execution framework; all work is
done by plugins(Plugin is a collection of one or more goals).
Looking for a specific goal to execute? This page lists the core
plugins and others. There are the build and the reporting plugins:
– Build plugins will be executed during the build and they should
be configured in the <build/> element from the POM.
– Reporting plugins will be executed during the site generation
and they should be configured in the <reporting/> element from
the POM/

15. Lifecycle
• A build lifecycle is an organized
sequence of phases that exist to
give order to a set of goals.
Those goals are chosen and
bound by the packaging type of
the project being acted upon.
There are three standard
lifecycles in Maven: clean, default
(sometimes called build) and site.

16. Command Syntax
• # syntax 1
centos:~/project # mvn <coordinate>:<goal>
centos:~/project # mvn
org.apache.maven.plugin:maven-help-
plugin:2.1:describe
• # syntax 2
centos:~/project # mvn <plugin>:<goal>
centos:~/project # mvn help:describe
• # syntax 3
centos:~/project # mvn <phase>
centos:~/project # mvn compile
<groupId>:<artifactId>:<version>:<goal>

17. Default/Build lifecycle phase
• Default
– Handle project building and deployment
validate compile test
packagedeploy install

18. Lifecycle – clean and site
phases
• Clean
– Cleaning target folder and generated file
• Site
– Generate documentation
pre-clean clean post-clean
pre-site site post-site site-deploy

19. Repositories
/<groupId>/<artifactId>/<version>/<artifactId>-<version>.<packaging>

20. Dependency Management
• transitive dependency

21. Site Generation and Reporting

22. POM component
• properties
• dependencies
• plugins
• parent
• modules
• dependencyManagement
• pluginManagement

23. POM component - properties
• centos:~/project # mvn clean package
• centos:~/project # mvn clean package -
Dmypackage.version=1.2-SNAPSHOT

24. POM component -
dependencies

25. POM component - plugins

26. Example 2
ref: Maven by Example

27. POM component - modules

28. POM component - parent

29. Optimize POM

30. POM component -
dependencyManagement

31. Maven repository
• Open Source:
– Apache Archiva
– JFrog Artifactory Open Source
– Sonatype Nexus OSS
• Commercial:
– JFrog Artifactory Pro
– Sonatype Nexus Pro
Ref: Best Practice - Using a Repository Manager

32. Sonatype Maven repository -
installation• # Setup firewall
centos:~ # firewall-cmd --zone=public --add-port=8081/tcp –
permanent
centos:~ # firewall-cmd --zone=public --add-service=http –
permanent
centos:~ # firewall-cmd –reload
• # Download & uncompress package
http://www.sonatype.org/nexus/go/
• # Run
centos:~ # /opt/nexus/bin/nexus start
centos:~ # /opt/nexus/bin/nexus stop
centos:~ # /opt/nexus/bin/nexus console
• # Browser
http://localhost:8081/nexus
Administrator (admin/admin123)
Depolyment (depolyment/depolyment123)

33. Hosted Repository - Nexus
Hosted Repository
Proxy Repository
Virtual Repository
Repository Group
Snapshot
Release

34. Hosted Repository - mvn deploy
~/.m2/settings.xml
project/pom.xml

35. Proxy Repository - Nexus

36. Maven Repository – method 1
~/.m2/settings.xml

37. Maven Repository – method 2
~/.m2/settings.xml

38. Repository Group- Nexus

39. Maven Project on Jenkins (1)

40. Maven Project on Jenkins (2)

41. Maven Project on Jenkins (3)

42. reference
• Apache Maven Project
• Maven by Example
• Maven Tutorial - TutorialsPoint