Writing Hibernate Configuration Files
In the previous section we completed the database setup and created required
table and populated with the data. In this section we will write required
hibernate configuration files.
For this tutorial we need following Hibernate configuration files:
Hibernate Configuration File
Hibernate configuration file (hibernate.cfg.xml) is used to provide the
information which is necessary for making database connections. The mapping
details for mapping the domain objects to the database tables are also a part of
Hibernate configuration file.
Here is the code of our Hibernate Configuration File:
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost/struts-hibernate</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password"></property>
<property name="hibernate.connection.pool_size">10</property>
<property name="show_sql">true</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<!-- Mapping files -->
<mapping resource="/roseindia/net/dao/hibernate/Tutorial.hbm.xml"/>
</session-factory>
</hibernate-configuration>
|
Place hibernate.cfg.xml file in the source directory e.g. "C:\Struts-Hibernate-Integration\code\src\java"
The <mapping resource=''> tag is used to specify the mapping file:
<mapping resource="/roseindia/net/dao/hibernate/Tutorial.hbm.xml"/>
Code of Tutorial.hbm.xml:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping auto-import="true" default-lazy="false">
<class
name="roseindia.net.dao.hibernate.Tutorial"
table="tutorials"
>
<id
name="id"
type="java.lang.Integer"
column="id"
>
<generator class="increment" />
</id>
<property
name="shortdesc"
type="java.lang.String"
column="shortdesc"
not-null="true"
length="50"
/>
<property
name="longdesc"
type="java.lang.String"
column="longdesc"
not-null="true"
length="250"
/>
<property
name="pageurl"
type="java.lang.String"
column="pageurl"
not-null="true"
length="100"
/>
</class>
</hibernate-mapping> |
Place Tutorial.hbm.xml file in the source directory e.g. "C:\Struts-Hibernate-Integration\code\src\java\roseindia\net\dao\hibernate\"
POJO Object
Here is the code of Java Bean object (Tutorial.java) used to store and retrieve
the data from database.
package roseindia.net.dao.hibernate;
import java.io.Serializable;
public class Tutorial implements Serializable {
/** identifier field */
private Integer id;
/** persistent field */
private String shortdesc;
/** persistent field */
private String longdesc;
/** persistent field */
private String pageurl;
/** full constructor */
public Tutorial(Integer id, String shortdesc, String longdesc, String pageurl) {
this.id = id;
this.shortdesc = shortdesc;
this.longdesc = longdesc;
this.pageurl = pageurl;
}
/** default constructor */
public Tutorial() {
}
public Integer getId() {
return this.id;
}
public void setId(Integer id) {
this.id = id;
}
public String getShortdesc() {
return this.shortdesc;
}
public void setShortdesc(String shortdesc) {
this.shortdesc = shortdesc;
}
public String getLongdesc() {
return this.longdesc;
}
public void setLongdesc(String longdesc) {
this.longdesc = longdesc;
}
public String getPageurl() {
return this.pageurl;
}
public void setPageurl(String pageurl) {
this.pageurl = pageurl;
}
}
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In this section we have created all the Hibernate related stuffs.
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Current Comments
5 comments so far (post your own) View All Comments Latest 10 Comments:i usually get SAX parse exception even the file is properly placed i also donot find any problem in validation with dtd. is there any soln. a warning i also get about to use log4j
Posted by sudhansu on Monday, 06.25.07 @ 10:55am | #20126
The <generator class = "increment"> in the <id> element tells hibernate to generate the primary key "id" by incrementing by 1.
Thanks
Deepak
Posted by Deepak Kumar on Friday, 04.6.07 @ 12:23pm | #13457
Should the POJO class always be Serializable? Why?
And what are the use of default constructors in the POJO class?
Posted by prosenjit on Friday, 04.6.07 @ 10:04am | #13448
In the Tutorial.hbm.xml file, what is the use of <generator class = "increment"> in the <id> element?
Posted by prosenjit on Friday, 04.6.07 @ 10:03am | #13447
Hi i'm trying to implement the above example but i got fatal exception . first of all i couldnt able to create sessionfactory. null pointer exception occured at the creating of sessionfactory. pls do advise me. Thanks
Posted by sarath koiloth ramath on Wednesday, 01.3.07 @ 12:26pm | #2528