Reputation: 4573
Student.java
package Model;
import java.util.Set;
public class Student {
private int studentID;
private String name;
private String city;
private Set<Address> AddressList;
private Set<Contact> ContactList;
public Set<Contact> getContactList() {
return ContactList;
}
public void setContactList(Set<Contact> contactList) {
ContactList = contactList;
}
public Set<Address> getAddressList() {
return AddressList;
}
public void setAddressList(Set<Address> addressList) {
AddressList = addressList;
}
public int getStudentID() {
return studentID;
}
public void setStudentID(int studentID) {
this.studentID = studentID;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
}
Address.java
package Model;
public class Address {
private int Aid;
private String fullAddress;
//private Student student;
/*public Student getStudent() {
return student;
}
public void setStudent(Student student) {
this.student = student;
}*/
public int getAid() {
return Aid;
}
public void setAid(int aid) {
Aid = aid;
}
public String getFullAddress() {
return fullAddress;
}
public void setFullAddress(String fullAddress) {
this.fullAddress = fullAddress;
}
}
Contact.java
package Model;
public class Contact {
private int contactId;
private String mobileNo;
public int getContactId() {
return contactId;
}
public void setContactId(int contactId) {
this.contactId = contactId;
}
public String getMobileNo() {
return mobileNo;
}
public void setMobileNo(String mobileNo) {
this.mobileNo = mobileNo;
}
}
Student.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="Model.Student" table="Student">
<id name="studentID" type="int">
<column name="StudentID" />
<generator class="identity" />
</id>
<property name="name" type="java.lang.String"/>
<property name="city" type="java.lang.String"/>
<set name="AddressList">
<key column="studentID"/>
<one-to-many class="Model.Address"/>
</set>
<set name="ContactList">
<key column="studentID"/>
<one-to-many class="Model.Contact"/>
</set>
</class>
Address.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="Model.Address" table="Address">
<id name="Aid" type="int">
<column name="Aid" />
<generator class="identity" />
</id>
<property name="fullAddress" type="java.lang.String"/>
</class>
Contact.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="Model.Contact" table="Contact">
<id name="contactId" type="int">
<column name="contactId" />
<generator class="identity" />
</id>
<property name="mobileNo" type="java.lang.String"/>
</class>
Main method.
public static void main(String[] args)
{
Configuration cfg=new Configuration();
cfg.configure("hibernate.cfg.xml");
SchemaExport se=new SchemaExport(cfg);
se.setOutputFile("D:\\abc.sql");
se.create(true,true);//create(boolean script, boolean export)
System.out.println("------------------Saving of Student--------------------");
Student student =new Student();
student.setName("Yograj");
student.setCity("Nanded");
Set<Address> addressList=new HashSet<Address>();
Address address=new Address();
address.setFullAddress("Chikhali Nanded");
addressList.add(address);
address=null;
address=new Address();
address.setFullAddress("karvenagar Pune");
addressList.add(address);
student.setAddressList(addressList);
Set<Contact> contactList=new HashSet<Contact>();
Contact contact=new Contact();
contact.setMobileNo("9403330577");
contactList.add(contact);
contact=null;
contact=new Contact();
contact.setMobileNo("9890864805");
contactList.add(contact);
student.setContactList(contactList);
boolean result=new StudentServices().SaveStudent(student);
if(result)
{
System.out.println("------------------Save Student succ..--------------------");
}
else
{
System.out.println("------------------Saving failed--------------------");
}
System.out.println("------------------Student Details--------------------");
List<Student> studentList=new StudentServices().GetStudentlist();
for (Student stud : studentList) {
System.out.println("Name:"+stud.getName());
System.out.println("City:"+stud.getCity());
for (Address add : stud.getAddressList()) {
System.out.println("Full Address:"+add.getFullAddress());
}
for (Contact cont : stud.getContactList()) {
System.out.println("Full Address:"+cont.getMobileNo());
}
}
System.out.println("Execution over.");
}
StudentService.Java
package Service;
import java.util.List;
import javassist.runtime.Inner;
import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.criterion.Restrictions;
import org.hibernate.sql.JoinType;
import Model.Address;
import Model.Contact;
import Model.Student;
public class StudentServices {
public boolean SaveStudent(Student student) {
try {
Configuration cfg = new Configuration().configure();
SessionFactory sf = cfg.buildSessionFactory();
Session session = sf.openSession();
Transaction transaction = session.beginTransaction();
session.save(student);
for (Address add : student.getAddressList()) {
session.save(add);
}
for (Contact cont : student.getContactList()) {
session.save(cont);
}
transaction.commit();
session.close();
return true;
} catch (HibernateException e) {
return false;
}
}
public List<Student> GetStudentlist() {
try {
Configuration cfg = new Configuration().configure();
SessionFactory sf = cfg.buildSessionFactory();
Session session = sf.openSession();
Transaction transaction = session.beginTransaction();
Criteria criteria = session.createCriteria(Student.class, "Student")
.createAlias("Student.AddressList", "Address",JoinType.INNER_JOIN)
.createAlias("Student.ContactList", "Contact",JoinType.INNER_JOIN);
List<Student> studentList = criteria.list();
transaction.commit();
session.close();
return studentList;
} catch (HibernateException e) {
return null;
}
}
}
When i execute main method hibernate will create database and table.in all table it will store records but when i fetch records using criteria API it gives me error "org.hibernate.LazyInitializationException."
Upvotes: 0
Views: 1301
Reputation: 21
For Junit testcases you need to bind an opened Session to the current Thread.
//the following is necessary for lazy loading
SessionFactory sf = null;
// open and bind the session for this test thread.
Session s = null;
// Session holder
SessionHolder holder = null;
BeanFactory beanFactory = null;
protected void onSetUp() throws Exception {
System.out.println("On SetUP----");
sf = (SessionFactory) beanFactory.getBean("sessionFactory");
s = sf.openSession();
TransactionSynchronizationManager.bindResource(sf, new SessionHolder(s));
}
protected void onTearDown() throws Exception {
System.out.println("On onTearDown----");
// unbind and close the session.
holder = (SessionHolder) TransactionSynchronizationManager.getResource(sf);
s = holder.getSession();
s.flush();
TransactionSynchronizationManager.unbindResource(sf);
SessionFactoryUtils.closeSession(s);
// SessionFactoryUtils.releaseSession(s, sf);
// teardown code here
}
If you want to no more care about LazyInitialisationException read this, its well explain what happens, and how to resolve the problem definitely
Upvotes: 0
Reputation: 5293
In your case student.addressList
and student.contactList
use lazy loading. Lazy loading means, the values are not loaded together with the studentList, but only then when you access them with getAddressList()
and getContactList
.
Lazy loading only works as long as the session is still open. If not yet loaded components are accessed after closing the session a LazyInitializationException is thrown, as in your example.
What you are doing is:
student.getAddressList()
This throws in exception in step 5, because you access the address list, which applies to lazy loading, and the data can't be loaded any more, because the session already was closed in step 3.
You must close the session after calling getAddressList()
and getContactList()
, then it works.
By the way, when you only read data as in GetStudentlist, then you do not need to begin a transaction, and you do not need to commit anything.
Upvotes: 1
Reputation: 2139
Try to access a method in student to initialize the proxy.
Try calling student.getAddress().getFullAddress() in your service method in order to initialize the proxy.
In this way, you will avoid the lazy initialization exception.
The other way is to set eager fetching to true, but i'd rather go with the first method first.
Upvotes: 0