Hibernate One To Many Annotation Example

Let us see an example on one to many annotations mapping…

Files required..

• Customers.java
• Vendor.java
• ForOurLogic.java
• hibernate.cfg.xml

Customers.java

package str;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "Customers")
public class Customers{

	@Id
	@Column(name = "custid")
	private int customerId;

	@Column(name = "custName", length=10)
	private String customerName;

	public int getCustomerId() {
		return customerId;
	}

	public void setCustomerId(int customerId) {
		this.customerId = customerId;
	}

	public String getCustomerName() {
		return customerName;
	}

	public void setCustomerName(String customerName) {
		this.customerName = customerName;
	}

}

Vendor.java

package str;

import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;
import javax.persistence.Table;

@Entity
@Table(name = "Vendor")

public class Vendor{

	@Id
	@Column(name = "vid")
	private int vendorId;

	@Column(name = "vname", length=10)
	private String vendorName;

	@OneToMany(fetch=FetchType.LAZY, targetEntity=Customers.class, cascade=CascadeType.ALL)
	@JoinColumn(name = "venid", referencedColumnName="vid")

	private Set children;

	public int getVendorId() {
		return vendorId;
	}

	public void setVendorId(int vendorId) {
		this.vendorId = vendorId;
	}

	public String getVendorName() {
		return vendorName;
	}

	public void setVendorName(String vendorName) {
		this.vendorName = vendorName;
	}

	public Set getChildren() {
		return children;
	}

	public void setChildren(Set children) {
		this.children = children;
	}	

}

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></mapping>
<mapping></mapping>
</session-factory>
</hibernate-configuration>

ForOurLogic.java

package str;

import java.util.HashSet;
import java.util.Set;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.cfg.Configuration;

public class ForOurLogic { 

	public static void main(String[] args)
	{

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

		SessionFactory factory = new AnnotationConfiguration().configure().buildSessionFactory();
		Session session = factory.openSession();		

	      Vendor v=new Vendor();
	      v.setVendorId(100);
	      v.setVendorName("java4s");

	      Customers c1=new Customers();
	      c1.setCustomerId(500);
	      c1.setCustomerName("customer1");

	      Customers c2=new Customers();
	      c2.setCustomerId(501);
	      c2.setCustomerName("customer2");

	      Set s=new HashSet();
	      s.add(c1);
	      s.add(c2);

	      v.setChildren(s);

	      Transaction tx=session.beginTransaction();
	           session.save(v);
	      tx.commit();

		session.close();
		System.out.println("One to Many Annotatios Done...!!!!!!");
		factory.close();
	}

}

Output

What you are thinkig....