Maven resource filtering not working

I recently ran into a problem when using maven resource filtering from within Eclipse. The problem was that properties in xml files (in this case a spring configuration file) weren’t expanded. Eventually i figured out what was causing the problem. That’s what this small blog is about.

Setup

As noted i wanted maven to expand some properties – datasource properties in this case – in a spring configuration file. The idea was to externalize the datasource connection information in various environment files, so that during deployment the right datasource connection information would be put in the spring configuration file according to the deployment environment, eg. local, test, staging.

For this i altered the spring conguration file, called spring-config.xml in my case, and changed the configuration for the dataSource spring bean into the one resembling the xml stanza below:

<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
  <property name="driverClassName">
    <value>oracle.jdbc.driver.OracleDriver</value>
  </property>
  <property name="url">
    <value>jdbc:oracle:thin:@${db.host}:${db.port}:${db.sid}</value>
  </property>
  <property name="username">
    <value>${db.user}</value>
  </property>
  <property name="password">
    <value>${db.password}</value>
  </property>
</bean>

This file was stored in the default resource directory src/main/resources.

The property files were put in the src/main/filters directory and were called filter-<env>.properties, eg. the filter-local.properties file looked like this:

#spring-config.xml
db.host=localhost
db.port=1521
db.sid=XE
db.user=scott
db.password=tiger

In the pom file i added the following code necessary for the property expanding:

<build>
  <filters>
    <filter>src/main/filters/filter_${env}.properties</filter>
  </filters>
  <resources>
    <resource>
      <directory>src/main/resources</directory>
      <filtering>true</filtering>
    </resource>
  </resources>
</build>
....
<profiles>
  <profile>
    <id>env-local</id>
    <properties>
      <env>local</env>
    </properties>
  </profile>
  <profile>
    <id>env-test</id>
    <properties>
      <env>test</env>
    </properties>
  </profile>
....
</profiles>

Now i used eclipse with the m2eclipse plugin and defined the following configuration for packaging the project (a web application) to a war file suitable for my local environment:

Notice the embedded Maven Runtime which is selected by default.

Problem

After running the configuration the properties for the datasource bean were not expanded and the original spring configuration file for the local deployment got packaged. I also noticed that maven properties in property text files as opposed to xml files, did get expanded. So the problem only occurred in xml files.

Solution

I noticed that running the package maven goal from a terminal window did expand the properties. So eventually i realized that the embedded maven version selected by default was the cause of distress. After i switched the maven runtime for the run configuration to the maven version currently installed on my ubuntu distribution, the problem was solved. See the picture below for this configuration.

The maven version on my ubuntu distribution, by the way, was installed via the following command:

sudo apt-get install maven2

Note that in future versions the bug in the maven embedded runtime may be fixed.

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