Example On Hibernate Criteria Query

Let us see an example program on hibernate criteria query,
files required….

• Product.java(POJO class)
• Product.hbm.xml
• hibernate.cfg.xml
• ForOurLogic.java (For writing our business logic)

Product.java

package str;

public class Product{

	private int productId;
	private String proName;
	private double price;

	public void setProductId(int productId)
	{
	    this.productId = productId;
	}
	public int getProductId()
	{
	    return productId;
	}

	public void setProName(String proName)
	{
	    this.proName = proName;
	}
	public String getProName()
	{
	    return proName;
	}

	public void setPrice(double price)
	{
	    this.price = price;
	}
	public double getPrice()
	{
	    return price;
	}
}

Product.hbm.xml

<?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="str.Product" table="products">

<id name="productId" column="pid"  />
<property name="proName" column="pname" length="10"/>
<property name="price"/>

    </class>
</hibernate-mapping>

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="connection.driver_class">oracle.jdbc.driver.OracleDriver
</property>
<property name="connection.url">jdbc:oracle:thin:@www.java4s.com:1521:XE</property>
<property name="connection.username">system</property>
<property name="connection.password">admin</property>

<property name="dialect">org.hibernate.dialect.OracleDialect</property>
<property name="show_sql">true</property>
<property name="hbm2ddl.auto">update</property>

<mapping resource="Product.hbm.xml"></mapping>
</session-factory>
</hibernate-configuration>

ForOurLogic.java

package str;

import java.util.Iterator;
import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.criterion.Criterion;
import org.hibernate.criterion.Restrictions;

public class ForOurLogic { 

	@SuppressWarnings("unchecked")
	public static void main(String[] args)
	{

		Configuration cfg = new Configuration();
		cfg.configure("hibernate.cfg.xml"); 

		SessionFactory factory = cfg.buildSessionFactory();
		Session session = factory.openSession();

		Criteria crit = session.createCriteria(Product.class);
		Criterion cn = Restrictions.gt("price",new Double(17000));
		crit.add(cn);
		List l=crit.list();
		System.out.println("List total size..._"+l.size());
		Iterator it=l.iterator();

		while(it.hasNext())
		{
			Product p=(Product)it.next();
			System.out.println(p.getProductId());
			System.out.println(p.getProName());
			System.out.println(p.getPrice());
			System.out.println("-----------------");
		}

		session.close();
		factory.close();
	}

}

Note:

• In line number 25, created object of Criteria
• In line number 26,  created Criterion interface object by using Restrictions class
• In line number 27, added criterion interface object to criteria object
• In line number 28,  executed criteria query by calling list() method in criteria
• See line number 34, in this case we must typecast into our POJO class type only

Actually the internal concept is,  once we called the list() method in criteria (line number 28) all objects (records) will come and stores in list object, from there we used to take iterate then typecast into our POJO class type bla bla.

What you are thinkig....