maven - read version number from property file

Question

I`m trying to read my build version number from a text file, and then assign it to the generated package name: myRelease-1.1.1.apk where the build number is manually set int

Answer 1

As you already got pom.xml, you don't need another extra properties file for define such a simple property, use POM's properties tag and override the default build finalName:

<properties>
  <final.build.version>1.1.1</final.build.version>
</properties>
<build>
  ... ...
  <finalName>${project.artifactId}-${final.build.version}</finalName>
  ... ...
</build>

If you use maven sign and zipalign your final apk at release stage, and want to override the final name here, use:

<build>
  <plugins>
    <plugin>
      <groupId>com.jayway.maven.plugins.android.generation2</groupId>
      <artifactId>android-maven-plugin</artifactId>
      <extensions>true</extensions>
      <inherited>true</inherited>
      <configuration>
        <undeployBeforeDeploy>true</undeployBeforeDeploy>
        <sign>
          <debug>false</debug>
        </sign>
        <zipalign>
          <verbose>true</verbose>
          <inputApk>${project.build.directory}/${project.artifactId}-${final.build.version}.apk</inputApk>
          <outputApk>${project.build.directory}/${project.artifactId}-${final.build.version}-signed-aligned.apk</outputApk>
        </zipalign>
        </configuration>
          <executions>
            <execution>
              <id>alignApk</id>
              <phase>package</phase>
              <goals>
                <goal>zipalign</goal>
              </goals>
            </execution>
          </executions>
      </plugin>
   </plugins>
</build>

EDIT:
If you have to use properties file, use properties-maven-plugin, check out similar SO question here.

Hope this help.

Answer 2

Just to answer my own question: it turns out that Maven needs the property to be set before anything can happen in the script. As such, it is set in stone and not modifiable from a file. I ended up writing an Ant task that modifies the pom.xml and changes the version in the file, before Maven script is triggered. Ugly and non-trivial, but it works.

Answer 3

I found I could work around this problem in maven by using the stuff about reading from the file suggested above, which does work for 'filtering' (putting stuff into a properties template file), so my application knows what version it is despite maven's confusion.

The reason I wanted it in the pom file is to put the version number into a couple of minified javascript file names so they wouldn't get cached across version updates... strictly speaking this doesnt require the actual version number so I used ${maven.build.timestamp} instead which outputs the date + time of the build in the format yyyymmdd-hhmm.

I think if I needed something more complex I'd start stripping stuff out into msbuild or something similar instead... Maven doesnt make things easy and after a year of battling it I dont really feel like its getting any better.

Answer 4

Read following answers:

• User and project specific settings in Maven
• How to read an external properties file in Maven
• Reading properties file from Maven POM file
• Read a file into a Maven property

or just:

<project>
  <build>
    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>properties-maven-plugin</artifactId>
        <version>1.0</version>
        <executions>
          <execution>
            <phase>initialize</phase>
            <goals>
              <goal>read-project-properties</goal>
            </goals>
            <configuration>
              <files>
                <file>dev.properties</file> <======== IT IS!!!!!
              </files>
            </configuration>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

UPDATE Working proof of concept is a subproject at http://sourceforge.net/u/gavenkoa/exp/ci/default/tree/maven/properties/pom.xml

Run build as mvn compile, check pom.xml and console output.