maven in 30 minutes

• use pom.xml to describe the project dependencies,such as third party jars used
• use pom.xml to describe the build process,such as using build plugin to achieve specific building process
• use pom.xml to manage multiple projects/modules, modules are in pom.xml, modules section
• a lot other stuff……

MAVEN Project produces an element, JAR,WAR or EAR, uniquely identified by a composite of fields known as groupId,artificatId,packing,version and scope. This vector of fields uniquely distinguishes a MAVEN artifact from all others.

the samples as follow:

groupid:artifactid:packaging:version:scope
org.springframework:spring:jar:4.3.2:compile

Phases,Plugins and Goals

• Build-in Maven Default Lifecycles:

• Site lifecycle

help: describe -Dplugin=
mvn help:effective-pom
mvn help:active-profiles

• declaring dependencies

<dependencies>
    <dependency> <groupId>com.yourcompany</groupId> <artifactId>yourlib</artifactId> <version>1.0</version> <type>jar</type> <scope>compile</scope>
    </dependency>
</dependencies> 

• declaring plugins

 <build>
        <plugins>
                <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-compiler-plugin</artifactId> <configuration>
                <maxmem>512m</maxmem> </configuration>
                </plugin> 
        </plugins>
</build>

scope in dependency:

To Understand the dependencies for whole project,you can use following commands:

mvn dependency:tree
mvn dependency:resolve  ## sorted
mvn dependency:resolve-plugins
mvn dependency:analyze

Repository is somewhere you can get the jars/wars

<repositories> 
    <repository>
        <id>JavaDotNetRepo</id>
        <url>https://maven-repository.dev.java.net</url> 
    </repository>
</repositories>

• Prefefined Properties
  

• self defined properties

<project>
    <properties>
        <my.somevar>My Value</my.somevar>
    </properties>
</project>

commands for debug:

mvn -e # stacktrace
mvn -X #
mvnDebug 

mvn -P profileName

profile setting:

<profiles> 
    <profile>
    <id>YourProfile</id> [...settings, build, etc...] 
        <activation>
            <os>
            <name>Windows XP</name> <family>Windows</family> <arch>x86</arch> <version>5.1.2600</version>
            </os> <file>
            <missing>somefolder/somefile.txt</missing> </file>
        </activation> 
    </profile>
</profiles>

##12- Maven Release

mvn release: repare
mvn release: perform

reports defined in reporting section, these reports could be coverage report, and any other reports.