Aggregation and Dependency of Projects
1 Aggregation
When a project is multi-module, how to build multiple modules at once instead of executing Maven commands separately under multiple modules.
1.1 Parent-Child Structure
<!--Parent Module netsales-poss In packaging Must be pom-->
<packaging>pom</packaging>
<!--Parent Module netsales-poss In pom.xml Introducing Submodules-->
<modules>
<module>poss-basic</module>
<module>poss-core</module>
<module>poss-openapi</module>
</modules>
1.2 Parallel Structure
<!--Parent Module netsales-parent In packaging Must be pom-->
<packaging>pom</packaging>
<!--Parent Module netsales-parent In pom.xml Introducing Submodules-->
<modules>
<module>../netsales-framework</module>
<module>../netsales-jobs</module>
</modules>
Paths in <modelu>can be understood as modulesPom.xmlRelative Path
When Maven's build command is executed in the parent module, Maven builds each module in turn based on the dependencies between the modules
2 Inheritance
Multiple subprojects require certain dependencies, so common dependencies of the subprojects can be extracted into the parent project, which can be easily managed through inheritance.
<!--poss-openapi Use in modules parent Label specifies parent module-->
<parent>
<groupId>com.aster.netsales.poss</groupId>
<artifactId>netsales-poss</artifactId>
<version>1.1.0</version>
</parent>
2.1 Dependency Management Dependency Inheritance
The parent module uses the dependency management tag to manage dependencies, and the child projects do not inherit by default and can configure inheritance.
<dependencyManagement>
<dependencies>
<!-- son pom Inheritance can be configured -->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>1.18.12</version>
</dependency>
<!-- son pom Not Inheritable -->
<dependency>
<groupId>io.swagger</groupId>
<artifactId>swagger-annotations</artifactId>
<version>1.5.6</version>
<optional>true</optional>
</dependency>
</dependencies>
</dependencyManagement>
When a child module configures a parent module's dependency in dependency management, it does not require a version and inherits from the parent project if the specified version represents the child pom's own, not the parent pom's
<dependencies>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<!-- Parent Project's swagger Is Inheritable -->
</dependencies>
2.2 dependencies Dependent Inheritance
The parent module uses the dependencies declared by <dependencies>and the child module inherits them all by default.