如何使用Maven运行多模块项目

Question

I'm trying to make my Java app modular, so that there will be the core base module that a client will have to aqcuire, but he/ she will be able to add additional features/ plugins as they come up, or as her needs extend. Like how IDEs like NetBeans go about it.

This is how far I've gone trying to implement this using Maven:

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I start by positioning myself in the workspace directory and creating the main (or parent project) by issuing the following Maven command:

mvn archetype:create -DgroupId=com.byteslounge.main -DartifactId=com-byteslounge-main 

Now you I delete the src folder since it will not be used. After this I edit my pom.xml file and change jar to pom.

After creating the main project I create the main library module. This is what a user will download and add extend by adding other modules to. From the main project directory, I issue the following Maven command:

mvn archetype:create -DgroupId=com.byteslounge.jar -DartifactId=com-byteslounge-jar 

Now I create the the first module by issuing the following command:

mvn archetype:create -DgroupId=com.byteslounge.lib -DartifactId=com-byteslounge-lib

This module should be called whenever the main program, com-byteslounge-jar, above is called.

How can I compile the project in maven in such a way that all modules get called whenever com-byteslounge-jar is run?

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PS:

Is this the best way to go about this, considering that I will later need to fully automate this by having an implementation of the The ServiceLoader Class in this project. I plan on having a sub-directory, called modules/ plugins, in the clients pc where any plugin applications will be included as .jar files. The main module (com-byteslounge-jar) will, when a user launches the application, include these other plugins in the final single program.

Answer 1

To expand on the link that @jan-doerrenhaus provides in the comments.

Your top level pom should reference the two sub-folders as 'modules' using something like this:

<modules>
    <module>com-byteslounge-jar</module>
    <module>com-byteslounge-lib</module>
</modules>

You then need to build your projects from the top level directory. Maven will automatically work out the dependency ordering to compile the projects in the correct ordering.

It's difficult to tell from your question, but you may be creating the sub-projects while in the wrong directory - you should create a folder for each of the sub projects, and then run the mvn archetype:create inside the subdirectory. You should have a directory structure which looks like this

com-byteslounge-jar/
com-byteslounge-jar/pom.xml
com-byteslounge-lib/
com-byteslounge-lib/pom.xml
pom.xml