Generating sql files in Maven using hibernate tools

Lars Vonk — Thu, 04 Dec 2008 21:42:01 +0000

Hibernate’s SessionFactory has some very powerful functions available like generating your tables from your hbm files using the hbm2ddl.auto property. This is very handy for laptop testing where you can let hibernate generate your complete scheme on the fly.
Although useful on your laptop, it is probably not want you want to do in a real environment. Luckily hibernate tools provides generating sql files via an Ant task. But if you are using Maven like me how can we integrate this in our build?

The answer is the maven-antrun-plugin. This plugin allows you to integrate ant tasks in Maven builds. To get the sql files we first create the Ant build.xml that will call the Ant task provided in the hibernate tools

In the above xml I declared the hibernatetool task via taskdef. Secondly, I created a target called generate-sql that I am going to call from the Maven build. The hibernatetool and hbm2ddl tasks are documented on the hibernate tools page, so checkout that if you need more info on how to configure.
As you can see I am using ${} properties. These are passed in from the Maven configuration. The file hibernate-for-sql-generation.properties contains the Dialect that Hibernate will use to generate the sql file.

Next is the relevant part of the pom.xml. Since I don't want to generate the sql each time I do a Maven build, I added it into a profile:

[/xml]

	generate-sql
	


				org.apache.maven.plugins
				maven-antrun-plugin
				1.3
				
					
						generate-sql
compile
						
							




								
									
								
							
								
						
							run
						
					
				
			
		
	

[xml]

The really interesting part starts from the execution tag. In here I tell the maven-antrun-plugin what to do. As you can see I pass in, amongst other things, the Maven test classpath. The classpath is needed by Ant to locate the org.hibernate.tool.ant.HibernateToolTask. Since I pass in the test classpath I added the hibernatetools jar as a dependency with scope test in the pom.xml.

When you now run mvn compile -Pgenerate-sql it will generate a sql file in the directory target/database. With some minor adjustments you are ready to use the generated file for creating your tables on all environments.

Lars

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Generating sql files in Maven using hibernate tools