Hibernate First Impression

Now, lets talk about object persistence framework. It is Hibernate. How to generate tables in database from POJOs (Plain Old Java Objects). All that you need are:
1. Eclipse as IDE
2. MySQL 5 as Database
We also need other libraries such as:
1. Hibernate-3.*
2. MySQL-connector-java-5.*
3. Jakarta-commons
4. X-Doclet-1.*

To generate tables in database from POJOs with hibernate, we need mapping files (*.hbm.xml) for that POJOs. As example, User.java (a POJO) need User.hbm.xml that will be used to map that POJO with table in database. We also need a hibernate configuration file (hibernate.cfg.xml). It is needed to configure database properties with hibernate. In this example we will generate both of *.hbm.xml and hibernate.cfg.xml by using X-Doclet and Ant. Let's start it.

Firstly create database named ndung in MySQL.


Create a java project in Eclipse named HibernateExample. Create a new folder named lib. It is used to place our libraries. Move all libraries above to folder lib. So in the lib folder, there are 4 folders inside. Also add a properties file in the lib folder named lib.properties. This is an example, my lib.properties. It show my libraries configuration. Make it in your own. Also configure build path our project into these libraries.

lib.properties

In source folder make java package named com.ndung.model and com.ndung.main. We will place our POJOs in com.ndung.model and main file in com.ndung.main. Create java classes in com.ndung.model named User.java and HibernateUtil.java. In other side, create java class named Main.java in com.ndung.main.

User.java


HibernateUtil.java


Main.java

Now, we will generate User.hbm.xml and hibernate.cfg.xml automatically by using X-Doclet and Ant. Make two xml files in the project named properties.xml and build.xml.

properties.xml


build.xml

To run Ant based on our own build.xml file, in Eclipse menu bar click Window, click Show View menu item, and click Ant menu item. Ant panel will show up in the right of Eclipse. Right click on that panel, click Add Buildfiles. Choose build.xml to add from HibernateExample project. 4 menus will show up in that panel below HibernateExample. Double click on hibernatedoclet. It will generate hibernate mapping files and also a hibernate configuration file. Check out in source folder, there are 2 new xml files. They are User.hbm.xml in /com/ndung/model folder and hibernate.cfg.xml.

User.hbm.xml


hibernate.cfg.xml

Then double click on run in Ant panel. Now, check out your database.


Btw, Long Live My Indonesia...