Spring Framework Interveiw Questions and Answers: Simple Hibernate Example ..!

Sunday, 28 July 2013

Simple Hibernate Example ..!

The files required to run the simple Hibernate Example.

1. Index.jsp
2. Web.xml
3. HibernateUtil.java
4. Person.java
5. hibernate.cfg.xml
6. Person.hbm.xml
7. server.xml

<%@ page import="java.io.*"%>
<%@ page import="java.util.*"%>
<%@ page import="mypackage.*"%>
<%@ page import="org.hibernate.*"%>
<%@ page import="org.hibernate.cfg.*"%>
<HTML>
 <HEAD>
  <title>Greetings!</title>
 </HEAD>
 <BODY>
  <%
org.hibernate.Session hibernateSession = mypackage.HibernateUtil.currentSession();
Transaction tx = hibernateSession.beginTransaction();

Person person = new Person();
person.setMyName("Joe");
hibernateSession.save(person);
tx.commit();
Query query = hibernateSession.createQuery("select p from Person as p where p.myName=:name");
query.setString("name", "Joe");
for (Iterator iter = query.iterate(); iter.hasNext()  {
person = (Person) iter.next();
}
HibernateUtil.closeSession();
%>
  <br>
  <br>
  <br>
  <br>
  <table width="400" border="0" cellspacing="1" cellpadding="0"
   align="center" class="tableBox">
   <tr>
    <td CLASS="bluebanner" align="center">
     Greetings,
     <%=person.getMyName()%></TD>
   </tr>
  </table>
 </BODY>
</HTML>

The web.xml is:

<!DOCTYPE web-app 
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN" 
"http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">

<web-app>

<display-name>hibernate</display-name>

<description>hibernate</description>

<!-- Servlets -->

<!-- Servlet Mappings -->


<!-- Session Expires in 1 day --> 
<session-config>
<session-timeout>1440</session-timeout>
</session-config>

<!-- The Welcome File List -->
<welcome-file-list>
<welcome-file>/WEB-INF/jsp/index.jsp</welcome-file>
</welcome-file-list>

<!-- Data Source References -->

<resource-ref>
<description>DB Connection</description>
<res-ref-name>jdbc/hibernate</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>

</web-app>

The Java source is in directory /WEB-INF/src:

package mypackage;
import org.hibernate.*;
import org.hibernate.cfg.*;

public class HibernateUtil {

private static final SessionFactory sessionFactory;

static {
try {
// Create the SessionFactory
sessionFactory = new Configuration().configure().buildSessionFactory();
} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.out.println("Initial SessionFactory creation failed: " + ex.getMessage());
throw new ExceptionInInitializerError(ex);
}
}

public static final ThreadLocal hibernateSession = new ThreadLocal();

public static Session currentSession() {
Session s = (Session) hibernateSession.get();
// Open a new Session, if this Thread has none yet
if (s == null) {
s = sessionFactory.openSession();
hibernateSession.set(s);
}
return s;
}

public static void closeSession() {
Session s = (Session) hibernateSession.get();
if (s != null)
s.close();
hibernateSession.set(null);
}
}

package mypackage;

public class Person {

private String myName;
private String id;

public String getId() {
return id;
}

private void setId(String id) {
this.id = id;
}


public String getMyName() {
return myName;
}

public void setMyName(String name) {
this.myName = name;
}
}

The hibernate.cfg.xml configuration files is:

<?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="connection.datasource">java:comp/env/jdbc/hibernate</property>
<property name="show_sql">true</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>

<!-- Mapping files -->
<mapping resource="Person.hbm.xml"/>

</session-factory>

</hibernate-configuration>

And the Person.hbm.xml file is:

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

<class name="mypackage.Person" table="Person">

<!-- A 32 hex character is our surrogate key. It's automatically
generated by Hibernate with the UUID pattern. -->
<id name="id" type="string" unsaved-value="null" >
<column name="id" sql-type="char(32)" not-null="true"/>
<generator class="uuid.hex"/>
</id>

<!-- A cat has to have a name, but it shouldn' be too long. -->
<property name="myName">
<column name="name" length="80" not-null="true"/>
</property>

</class>

</hibernate-mapping>

The context xml for this example in Tomcat's server.xml is:


<Context path="/Hibernate" reloadable="true" docBase="C:\eclipse\workspace\Hibernate" workDir="C:\eclipse\workspace\hibernate\work">
<Resource name="jdbc/hibernate" scope="Shareable" type="javax.sql.DataSource"/>
<ResourceParams name="jdbc/hibernate">
<parameter>
<name>url</name>
<value>jdbc:mysql://127.0.0.1:3306/hibernate</value>
</parameter>

<parameter>
<name>maxIdle</name>
<value>2</value>
</parameter>
<parameter>
<name>maxActive</name>
<value>2000</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>com.mysql.jdbc.Driver</value>
</parameter>
<parameter>
<name>maxWait</name>
<value>5000</value>
</parameter>
<parameter>
<name>username</name>
<value>root</value>
</parameter>
<parameter>
<name>password</name>
<value></value>
</parameter>
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
</ResourceParams>
</Context>

Good luck!

Spring Framework Interveiw Questions and Answers

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Sunday, 28 July 2013

Simple Hibernate Example ..!

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