maven 之aggregation and inheritance

Aggregation例子：

<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>org.codehaus.mojo</groupId>
<artifactId>my-parent</artifactId>
<version>2.0</version>
<packaging>pom</packaging>

<modules>
<module>my-project</module>
<module>another-project</module>
</modules>
</project>

Inheritance例子：
<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">
<parent><pre name="code" class="html"><groupId>org.codehaus.mojo</groupId>
<artifactId>my-parent</artifactId>

<pre name="code" class="html"><version>2.0</version>

</parent>

<modelVersion>4.0.0</modelVersion>

<groupId>org.codehaus.mojo</groupId> <artifactId>my-child</artifactId> <version>2.0</version> <packaging>jar</packaging> </project>

关于这两个关系的注意点，摘抄自maven官网：

A final note on Inheritance v. Aggregation

Inheritance and aggregation create a nice dynamic to control builds through a single, high-level POM. You will often see projects that are both parents and aggregators. For example, the entire maven core runs through a single base POM org.apache.maven:maven, so building the Maven project can be executed by a single command: mvn compile. However, although both POM projects, an aggregator project and a parent project are not one in the same and should not be confused. A POM project may be inherited from - but does not necessarily have - any modules that it aggregates. Conversely, a POM project may aggregate projects that do not inherit from it.