No more .hbm.xml files

[Fabrizio Gianneschi]

Here's a question for Hibernate experts:

Is there a way to avoid populating the classpath (and source path) with .hbm.xml files?

I honestly prefer the "monolithic" configuration file approach, so can someone tell me why this practice is considered bad on Hibernate when defining the mappings?

Thanks in advance

[Christian Bauer]

It's common practice to use a file per persistent class (hierarchy), and some tools (middlegen, hbm2java) expect and generate this format only. If you don't follow it and have a single huge mapping file, you only have the disadvantages of maintaining that single file. I usually find it easier to seperate my mappings, even in small projects.

[pascal betz]

have an ant task to generate your mapping files with xDoclet, put them in a jar, add only one file to the classpath.

pascal

[MK Lee]

the hbm.xml is well-supported by the Hibernate Ext that comes along.
I just need to write the hbm.xml file and build.xml then generate the java class & db script in no time.

[somkiat puisungnoen]

I'm use Hibernate extension tool for generate persistent with ant like this

  <target name="generate" description="Generate Hibernate Source File">
<java classname="net.sf.hibernate.tool.hbm2java.CodeGenerator" fork="true" dir=".">
<classpath>
<fileset dir="${lib}">
<include name="**/*.jar" />
</fileset>
</classpath>
<arg value="--output=${src}"/>
<arg value="--config=config-hbm.xml"/>
<arg value="${src}/com/spns/hbm/Team.hbm.xml"/>
<arg value="${src}/com/spns/hbm/Player.hbm.xml"/>
<arg value="${src}/com/spns/hbm/TestTable.hbm.xml"/>
</java>
</target>

And you can use XDoclet to generate persistent class ,So see detail at
http://www.hibernate.org/72.html

[Rickard Sundin]

If you want to avoid clobbering your source code tree with a lot of hbm.xml-files, and also to avoid maintaining all hibernate configuration in a single file, try putting all mapping files (one per class) in a directory of their own. If you do that you will have to configure your SessionFactory with the names of the mapping files instead of the name of the classes.

/Rickard

[somkiat puisungnoen]

Originally posted by Rickard Johansson:
If you want to avoid clobbering your source code tree with a lot of hbm.xml-files, and also to avoid maintaining all hibernate configuration in a single file, try putting all mapping files (one per class) in a directory of their own. If you do that you will have to configure your SessionFactory with the names of the mapping files instead of the name of the classes.

/Rickard

Do you have example to do that ?

[Rickard Sundin]

Put the hbm.xml files in a directory 'mappings' (or whatever you like) in the root of your classpath.

Configuration cfg = new Configuration()
    .addFile("mappings/Item.hbm.xml")
    .addFile("mappings/Bid.hbm.xml");

/Rickard

[Rickard Sundin]

Or if you use the xml-style configuration file:

<hibernate-configuration>
  <session-factory>
    <!-- add your properties and stuff -->
    <mapping resource="mappings/Item.hbm.xml"/>
    <mapping resource="mappings/Bid.hbm.xml"/>
  </session-factory>
</hibernate-configuration>

[somkiat puisungnoen]

Originally posted by Rickard Johansson:
Put the hbm.xml files in a directory 'mappings' (or whatever you like) in the root of your classpath.

Configuration cfg = new Configuration()
    .addFile("mappings/Item.hbm.xml")
    .addFile("mappings/Bid.hbm.xml");

/Rickard

or
An alternative (sometimes better) way is to let Hibernate load a mapping file using getResourceAsStream():

Configuration cfg = new Configuration()
    .addClass(org.hibernate.auction.Item.class)
    .addClass(org.hibernate.auction.Bid.class);
 

Then Hibernate will look for mapping files named /org/hibernate/autcion/Item.hbm.xml and /org/hibernate/autcion/Bid.hbm.xml in the classpath. This approach eliminates any hardcoded filenames.