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Hibernate Many-To-One Mapping Example part -2

  Now create the hibernate configuration file and add all the mapping files.

01.<?xml version="1.0" encoding="UTF-8"?>
02.<!DOCTYPE hibernate-configuration PUBLIC
03."-//Hibernate/Hibernate Configuration DTD 3.0//EN"
05.<hibernate-configuration>
06.<session-factory>
07.<property name="hibernate.connection.driver_class"> org.hsqldb.jdbcDriver </property>
08.<property name="hibernate.connection.url"> jdbc:hsqldb:hsql://localhost<;/property>
09.<property name="hibernate.connection.username">sa</property>
10.<property name="connection.password"></property>
11.<property name="connection.pool_size">1</property>
12.<property name="hibernate.dialect"> org.hibernate.dialect.HSQLDialect </property>
13.<property name="show_sql">true</property>
14.<property name="hbm2ddl.auto">create-drop</property>
15.<mapping resource="com/vaannila/student/Student.hbm.xml"/>
16.<mapping resource="com/vaannila/student/Address.hbm.xml"/>
17.</session-factory>
18.</hibernate-configuration>
After creating the configuration file, generate java class files using Hibernate Tools.(To generate code using Hibernate Tools refer this example )
The following classes will be generated.

package com.vaannila.student;
02. 
03.// Generated Sep 3, 2009 7:20:37 PM by Hibernate Tools 3.2.4.GA
04. 
05./**
06.* This class contains student details.
07.*/
08.public class Student implements java.io.Serializable {
09. 
10.private long studentId;
11.private String studentName;
12.private Address studentAddress;
13. 
14.public Student() {
15.}
16. 
17.public Student(String studentName, Address studentAddress) {
18.this.studentName = studentName;
19.this.studentAddress = studentAddress;
20.}
21. 
22.public long getStudentId() {
23.return this.studentId;
24.}
25. 
26.public void setStudentId(long studentId) {
27.this.studentId = studentId;
28.}
29. 
30.public String getStudentName() {
31.return this.studentName;
32.}
33. 
34.public void setStudentName(String studentName) {
35.this.studentName = studentName;
36.}
37. 
38.public Address getStudentAddress() {
39.return this.studentAddress;
40.}
41. 
42.public void setStudentAddress(Address studentAddress) {
43.this.studentAddress = studentAddress;
44.}
45. 
46.}

01.package com.vaannila.student;
02. 
03.// Generated Sep 3, 2009 7:20:37 PM by Hibernate Tools 3.2.4.GA
04. 
05./**
06.* This class contains the student's address
07.*          details.
08.*/
09.public class Address implements java.io.Serializable {
10. 
11.private long addressId;
12.private String street;
13.private String city;
14.private String state;
15.private String zipcode;
16. 
17.public Address() {
18.}
19. 
20.public Address(String street, String city, String state, String zipcode) {
21.this.street = street;
22.this.city = city;
23.this.state = state;
24.this.zipcode = zipcode;
25.}
26. 
27.public long getAddressId() {
28.return this.addressId;
29.}
30. 
31.public void setAddressId(long addressId) {
32.this.addressId = addressId;
33.}
34. 
35.public String getStreet() {
36.return this.street;
37.}
38. 
39.public void setStreet(String street) {
40.this.street = street;
41.}
42. 
43.public String getCity() {
44.return this.city;
45.}
46. 
47.public void setCity(String city) {
48.this.city = city;
49.}
50. 
51.public String getState() {
52.return this.state;
53.}
54. 
55.public void setState(String state) {
56.this.state = state;
57.}
58. 
59.public String getZipcode() {
60.return this.zipcode;
61.}
62. 
63.public void setZipcode(String zipcode) {
64.this.zipcode = zipcode;
65.}
66. 
67.}

01.package com.vaannila.student;
02. 
03.import org.hibernate.HibernateException;
04.import org.hibernate.Session;
05.import org.hibernate.Transaction;
06. 
07.import com.vaannila.util.HibernateUtil;
08. 
09.public class Main {
10. 
11.public static void main(String[] args) {
12.Session session = HibernateUtil.getSessionFactory().openSession();
13.Transaction transaction = null;
14.try {
15.transaction = session.beginTransaction();
16.Address address = new Address("OMR Road""Chennai""TN","600097");
17.//By using cascade=all option the address need not be saved explicitly when the student object is persisted the address will be automatically saved.
18.//session.save(address);
19.Student student1 = new Student("Eswar", address);
20.Student student2 = new Student("Joe", address);
21.session.save(student1);
22.session.save(student2);
23.transaction.commit();
24.catch (HibernateException e) {
25.transaction.rollback();
26.e.printStackTrace();
27.finally {
28.session.close();
29.}
30. 
31.}
32. 
33.}
On executing the Main class you will see the following output.
The Student table has two records.


The Address table has one record.


Both the student records points to the same address record, this illustrates the many-to-one mapping.
The folder structure of the example is shown below.











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