A simple Hibernate sample

Some days ago. I bought a book named Java Persistence with Hibernate.

Now , I will show a simple sample for everybody who wanna learn the skill of Hibernate.

Step one.

Create a class named Message,Of course ,you should have created a project in IDE.

Message.java
package hello;

public class Message {
private Long id;
private String text;
private Message nextMessage;
Message()
{

}
public Message(String text)
{
this.text = text;
}
public Long getId() {
return id;
}

public void setId(Long id) {
this.id = id;
}

public Message getNextMessage() {
return nextMessage;
}

public void setNextMessage(Message nextMessage) {
this.nextMessage = nextMessage;
}

public String getText() {
return text;
}

public void setText(String text) {
this.text = text;
}

}

Step two.

create a XML named Message.hbm.xml.Just like the following.

Message.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="hello.Message" table ="MESSAGES">
<id name="id" column="MESSAGE_ID">
<generator class="increment"/>
</id>
<property name="text" column="MESSAGE_TEXT"/>
<many-to-one name="nextMessage" cascade="all" column="NEXT_MESSAGE_ID" foreign-key="FK_NEXT_MESSAGE"/>
</class>
</hibernate-mapping>

Step three.

Write you property file.

hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.dialect">org.hibernate.dialect.Oracle9Dialect</property>
<property name="hibernate.connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="hibernate.connection.url">jdbc:oracle:thin:@126.1.1.63:1521:oradb</property>
<property name="hibernate.connection.username">timesheet</property>
<property name="hibernate.connection.password">timesheet</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.use_sql_comments">true</property>
<property name="hibernate.hbm2ddl.auto">create</property>
<mapping resource="hello/Message.hbm.xml"/>
</session-factory>
</hibernate-configuration>

Step four

Configurating you DataBase,and run the main method like this

Oh.I forgot that ,before you run this project ,you'd better create a manage bena for Hibernate.

I write a class named HibernateUtil.

HibernateUtil.java

package persistence;

import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtil {
private static SessionFactory sessionFactory;
static
{
try
{
sessionFactory = new Configuration().configure().buildSessionFactory();
}
catch(Throwable ex)
{
throw new ExceptionInInitializerError(ex);
}
}
public static SessionFactory getSessionFactory()
{
return sessionFactory;
}
public static void shutdown()
{
getSessionFactory().close();
}
}

then you should have the Main Class lik this.

package hello;

import org.hibernate.*;
import java.util.*;
import persistence.*;

/**
*
* @author zhangqi
*/
public class HelloWorld {

public static void main(String[] args)
{
Session session = HibernateUtil.getSessionFactory().openSession();
Transaction tx = session.beginTransaction();
Message message = new Message("Hello World2");
Long msgId =(Long)session.save(message);
System.out.println(msgId);
tx.commit();;
session.close();

Session newSession = HibernateUtil.getSessionFactory().openSession();
Transaction newTx = newSession.beginTransaction();
List messages = newSession.createQuery("from Message m order by m.text asc").list();
System.out.println(messages.size()+" message(s) found:");

for(Iterator iter = messages.iterator();iter.hasNext();)
{
Message loadedMsg =(Message)iter.next();
System.out.println(loadedMsg.getId() +" "+loadedMsg.getText());
}
newTx.commit();;
newSession.close();
HibernateUtil.shutdown();

}
}
Yeah.run it ,you will get the answer