Maven Combat (vi)--aggregation and inheritance of sub-modules

1. Concepts of aggregation and inheritance

Aggregation: Put multiple projects together to run

New parent project, adding in Pom.xml

<modules> < Module>SIP-utils</module>< Module>SIP-web</module>< Module>SIP-SQL</module>< Module>SIP-core</module></modules>

These are the projects that are aggregated so that mvn clean install this pro will also package the above items

Inheritance: For example, if you use JUnit for a project, you can create a Jutint parent class like Java

Then we can inherit a parent project in the project and configure it as follows in Pom.xml

    <parent>        <groupId>com.learnPro</groupId>        <artifactId>SIP-parent</artifactId>        <version>0.0.1-SNAPSHOT</version>    </parent>

2. Building sub-modules from the command line

For example, the module structure we need to build is as follows:

2.1 Building the parent module pro-parent

mvn org.apache.maven.plugins:maven-archetype-plugin:2.2-DgroupId=com.-DartifactId=pro-parent-DarchetypeArtifactId=maven-archetype-quickstart

There was a problem here, before the following command, but build does not pass

-DgroupId=com.-DartifactId=pro-parent-DarchetypeArtifactId=maven-archetype-quickstart

Workaround, please refer to: http://josh-persistence.iteye.com/blog/2258213

With the above command you can see that our project has been created successfully
At this point, we can delete the Src folder (because the parent item is just a container, no code required)
Modify the Pom.xml file, modify the jar to Pom,pom to indicate that it is an inherited module, and modify the contents as follows

<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.learnpro</groupId>  <artifactid>Pro-parent</artifactid>  <version>1.0-snapshot</version>  <packaging>Pom</Packaging><!--change from jar to pom-->  <name>Pro-parent</name>  <URL>http://maven.apache.org</URL>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  </Properties>  <dependencies>    <dependency>      <groupId>Junit</groupId>      <artifactid>Junit</artifactid>      <version>3.8.1</version>      <scope>Test</Scope>    </Dependency>  </dependencies></Project>

2.2 Building sub-modules DAO

Run the following command in the previous folder

cd pro-parentmvn org.apache.maven.plugins:maven-archetype-plugin:2.2-DartifactId=pro-dao-DarchetypeArtifactId=maven-archetype-quickstart

After the compilation is successful, the following is automatically added in the Pro-parent pom.xml

  <modules>    <module>pro-dao</module>  </modules>

Let's take a look at Pro-dao's pom file.

<?xml version= "1.0"?><project xsi:schemalocation="http://maven.apache.org/POM/4.0.0/HTTP// Maven.apache.org/xsd/maven-4.0.0.xsd " xmlns=" http://maven.apache.org/POM/4.0.0 "xmlns : xsi="Http://www.w3.org/2001/XMLSchema-instance">      <modelversion>4.0.0</modelversion>  <parent>    <groupId>Com.learnpro</groupId>    <artifactid>Pro-parent</artifactid>    <version>1.0-snapshot</version>  </Parent>  <groupId>Com.learnpro</groupId>  <artifactid>Pro-dao</artifactid>  <version>1.0-snapshot</version>  <name>Pro-dao</name>  <URL>http://maven.apache.org</URL>  <properties>    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>  </Properties>  <dependencies>    <dependency>      <groupId>Junit</groupId>      <artifactid>Junit</artifactid>      <version>3.8.1</version>      <scope>Test</Scope>    </Dependency>  </dependencies></Project>

Here, it automatically adds <parent> , we need to put in <groupId>com.learnpro</groupId>和<version>1.0-SNAPSHOT</version>去掉，并加上<packaging>jar</packaging> , because we already have a parent module, GroupID and version inherit the GroupID and version from the parent module, and finally set the packaging packaging method to Jar

3.eclipse plug-in Build project 3.1 build parent Project

右键->new->other->搜索maven，选择Maven Project

3.2 Building sub-modules

右键->new->other->搜索maven，选择Maven Module

Then next, and then select the MAVEN project model, you can create the corresponding sub-modules
At the same time, we can find that the pro-parent Pom file also adds the following content

  <modules>    <module>pro-children</module>  </modules>

At this time, we also need to<groupId>com.learnpro</groupId>和<version>1.0-SNAPSHOT</version>去掉，并加上<packaging>jar</packaging>

3.3 Importing MAVEN Projects

右键->Import->搜索maven，选择Existing Maven Project

Choose the pro-parent we built earlier.

Maven Combat (vi)--aggregation and inheritance of sub-modules