Maven 中的继承与聚合

先贴一个parent 模块的pom.xml

<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>com.mycompany.myproject</groupId>
<artifactId>myproject-parent</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>pom</packaging>

<name>myproject-parent</name>
<url>http://maven.apache.org</url>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<spring.version>3.2.6.RELEASE</spring.version>
</properties>

<modules>
<module>../example</module>
</modules>

<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>${spring.version}</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring.version}</version>
</dependency>
</dependencies>
</dependencyManagement>

<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency> <!--for org.hamcrest.Matchers-->
<groupId>org.hamcrest</groupId>
<artifactId>hamcrest-library</artifactId>
<version>1.3</version>
<scope>test</scope>
</dependency>

<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>

</dependencies>
</project>

子模块的pom.xml

<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>

<parent>
<groupId>com.mycompany.myproject</groupId>
<artifactId>myproject-parent</artifactId>
<version>0.0.1-SNAPSHOT</version>
<relativePath>../myproject-parent/pom.xml</relativePath>
</parent>

<artifactId>peter-user</artifactId>
<packaging>war</packaging>

<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
</dependency>
<dependency>
<groupId>or
b2e3
g.springframework</groupId>
<artifactId>spring-core</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
</dependency>
</dependencies>
</project>

继承：

1.子模块可以继承parent中所有关于GAV的属性，artifactId除外

2.子模块可以继承parent中properties

3.子模块可以继承parent中的dependencies，比如子模块都不用再添加log4j的依赖了，

但是这样也容易导致子模块中添加了不需要的模块。此时需要使用dependencyManagement，子模块pom.xml中只需要添加GA，这样也省去了很多麻烦。

聚合：

将所有开放的子模块使用modules打包，这样就不需要每个模块单独编译，打包了。