Configuration through a hibernate.properties-File

The most simple way to configure the plugin is, to put all the hibernate-configuration in a hibernate.properties-file on your classpath. Put the file in the resources-folder. Maven will put it in the class-folder of your webapp, where it will be picked up by this plugin as well as by Hibernate 4.

Doing so, the only additionally configuration needed, to activat the plugin is the following entry in the plugins-section of your pom.xml:

<plugin>
  <groupId>de.juplo</groupId>
  <artifactId>hibernate4-maven-plugin</artifactId>
  <version>1.0.5</version>
  <executions>
    <execution>
      <goals>
        <goal>export</goal>
      </goals>
    </execution>
  </executions>
</plugin>

But be aware, that in this case the database-url, that is build in the application is the same that is used while testing, where the database is droped and recreated by the plugin. Because of that, you should never fire up this configuration on your production system, or your database might be erased!

A better approach is, to specify a different url for testing like in the following snippet:

<plugin>
  <groupId>de.juplo</groupId>
  <artifactId>hibernate4-maven-plugin</artifactId>
  <version>1.0.5</version>
  <executions>
    <execution>
      <goals>
        <goal>export</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <url><![CDATA[jdbc:mysql://localhost/test-db]]></url>
  </configuration>
</plugin>

Configuration properties, that are set in the configuration-section of the plugin-configuration cannnot be overwritten elsewere (for details see Configuration-Method-Precedence). You never can overwrite them by accident when specifying a property on the commandline or in your settings.xml.

Configuration through maven-properties

Alternatively, it is possible, to configure the plugin via maven-properties. Each relevant configuration-option has a corresponding maven-property (for a full list see the Documentation of the export-Mojo). These are named after the Hibernate JDBC Properties:

• hibernate.connection.driver_class
• hibernate.dialect
• hibernate.connection.url
• hibernate.connection.username
• hibernate.connection.password

So, instead of writing the hibernate-configuration in the properties-file, like above, you could put it in the properties-section of your pom.xml.

Thogether with the plugin-definition from above, the following would be a complete configuration (again, the database-url was overwritten in the plugin-configuration, to be sure to have a separate database for testing):

<properties>
  <hibernate.connection.driver_class>org.hsqldb.jdbcDriver</hibernate.connection.driver_class>
  <hibernate.dialect>org.hibernate.dialect.HSQLDialect</hibernate.dialect>
  <hibernate.connection.url><![CDATA[jdbc:hsqldb:res:org.my.path.production_db]]></hibernate.connection.url>
  <hibernate.connection.username>sa</hibernate.connection.username>
  <hibernate.connection.password></hibernate.connection.password>
</properties>

...

<plugins>

  ...

  <plugin>
    <groupId>de.juplo</groupId>
    <artifactId>hibernate4-maven-plugin</artifactId>
    <version>1.0.5</version>
    <executions>
      <execution>
        <goals>
          <goal>export</goal>
        </goals>
      </execution>
    </executions>
    <configuration>
      <url><![CDATA[jdbc:hsqldb:target/db/testdb;shutdown=true]]></url>
    </configuration>
  </plugin>

<plugins>

Configuration through the plugin-configuration

A third way for configuring the plugin is the plugin-configuration. The relevant configuration-parameters are:

• driverClassName
• hibernateDialect
• url
• username
• password

The equivalent of the configuration from the last section would look like this:

<plugin>
  <groupId>de.juplo</groupId>
  <artifactId>hibernate4-maven-plugin</artifactId>
  <version>1.0.5</version>
  <executions>
    <execution>
      <goals>
        <goal>export</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <driverClassName>org.hsqldb.jdbcDriver</driverClassName>
    <hibernateDialect>org.hibernate.dialect.HSQLDialect</hibernateDialect>
    <url><![CDATA[jdbc:hsqldb:target/db/fotos;shutdown=true]]></url>
    <username>sa</username>
    <password></password>
  </configuration>
</plugin>

The parameter hibernateProperties (name of the hibernate-properties-file to use, defaults to hibernate.properties) can only be configured through this approach.

For more explanations, see the Documentation of the export-Mojo.

Configuration-Method-Precedence

The configuration is gathered in a fix order:

1. hibernate.properties
2. maven-properties
3. plugin-configuration

If you are in doubt about where a configuration-value comes from, run maven with the debug-output enabled: mvn -X hibernate4:export and be aware, that maven-properties can be overwitten on the command-line, in your ~/.m2/settings.xml and in a profile.

The plugin-configuration comes last and overwrites everything else. That way, you can be sure, that a configuration-value, that is specified in the plugin-configuration will never be overwritten by any other configuration-method.

If you need to overwrite plugin-configuration-values with maven-properties, you can use maven-properties in the plugin-configuration:

<plugin>
  <groupId>de.juplo</groupId>
  <artifactId>hibernate4-maven-plugin</artifactId>
  <version>1.0.5</version>
  <executions>
    <execution>
      <goals>
        <goal>export</goal>
      </goals>
    </execution>
  </executions>
  <configuration>
    <password>${my-password-property}</password>
  </configuration>
</plugin>