fetchlibs-maven-plugin

A Maven plugin for downloading all specified dependencies into one folder. Then they can be added into classpath and used within your application:

java -cp 'tinyApp.jar;./libs/*' cz.cesal.app.Start

• Why
• Setup
  • [Building your application - add depends-maven-plugin]
  • [Release POM - add this plugin (fetchlibs-maven-plugin)]
• Usage

Why?

It is faster to fetch only your application when you release it and not all unchanged dependencies. With fat-jar, you are always downloading hundreds of megabytes, but with this plugin, you can fetch only a few kB!

Setup

You typically use this plugin when downloading compiled JAR from your repository into production server. After download of released JAR, plugin looks into it and fetches all specified dependencies.

Building your application - add depends-maven-plugin

When building your application, depends-maven-plugin adds file with a list of all dependencies.

<plugin>
    <groupId>org.apache.servicemix.tooling</groupId>
    <artifactId>depends-maven-plugin</artifactId>
</plugin>

This list is included in released JAR and then used later when fetching released JAR. For downloading your released JAR, you can use maven-dependency-plugin (install:copy).

Release POM - add this plugin (fetchlibs-maven-plugin)

Add this snippet into your pom.xml:

<build>
  <plugins>
    ...
    <plugin>
      <groupId>cz.cesal</groupId>
      <artifactId>fetchlibs-maven-plugin</artifactId>
      <version>1.0.0-SNAPSHOT</version>
      <configuration>
       	<source>app.jar</source>
			<target>libs</target>
			<startClassToFile>startClass.txt</startClassToFile>
      </configuration>
      <executions>
				<execution>
					<phase>install</phase>
					<goals>
						<goal>fetchlibs</goal>
					</goals>
				</execution>
			</executions>
    </plugin>
    ...
  </plugins>
</build>

Usage

You can build an image with the above configuration by running this command:

mvn fetchlibs:fetchlibs

If you replace source parameter value with for example ${app.filename}, you can use:

mvn fetchlibs:fetchlibs -Dapp.filename=other-name.jar

You can parametrize other parameters as well.