Hibernate ORDER BY Clause
In this tutorial you will learn about HQL ORDER BY clause.
Purpose for using ORDER BY clause is similar to that it is used in SQL to sort the records. By default records are sorted in ascending order to sort records in descending order 'desc' can be used with the query.
Example
Here I am giving a simple example which will demonstrate you how a HQL order by clause can be used. To achieve the solution of such problem at first I have created a table named employee with the field 'Id' and 'Name'. Next created a POJO / Persistent class named Employee to fetch the persistent object, a hibernate.cfg.xml file that the Hibernate can utilize it to create connection pool and the required environment setup, an employee.hbm.xml file to map an Employee object with table employee. And finally create a simple java file into which we will use HQL order by clause for sorting the data from the database.
Complete Code :
Employee.java
package roseindia;
public class Employee {
private int id;
private String name;
public Employee()
{
}
public Employee(String name)
{
this.name = name;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
employee.hbm.xml
<?xml version='1.0'?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="roseindia"> <class name="Employee" table="employee"> <id name="id" type="int" column="Id" > <generator class="assigned"/> </id> <property name="name"> <column name="Name" /> </property> </class> </hibernate-mapping>
HibernateOrderByClause
package roseindia;
import java.util.List;
import java.util.Iterator;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;
import org.hibernate.service.ServiceRegistryBuilder;
public class HibernateOrderByClause {
private static SessionFactory sessionFactory;
private static ServiceRegistry serviceRegistry;
public static void main(String args[]) {
Session session = null;
try {
try {
Configuration cfg = new Configuration().addResource(
"roseindia/employee.hbm.xml").configure();
serviceRegistry = new ServiceRegistryBuilder().applySettings(
cfg.getProperties()).buildServiceRegistry();
sessionFactory = cfg.buildSessionFactory(serviceRegistry);
} catch (Throwable th) {
System.err.println("Failed to create sessionFactory object."
+ th);
throw new ExceptionInInitializerError(th);
}
session = sessionFactory.openSession();
Query orderByClause = session
.createQuery("select emp from Employee emp order by emp.name");
List<Employee> empList = orderByClause.list();
System.out.println("Displaying id from table employee");
Iterator<Employee> it = empList.iterator(); //orderByClause.iterate();
System.out.println("Id \t Name");
while(it.hasNext())
{
Employee emp = (Employee)it.next();
System.out.println(emp.getId() +"\t"+ emp.getName());
}
} catch (Exception e) {
System.out.println(e.getMessage());
} finally {
session.close();
}
}
}
hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <property name="hibernate.connection.url">jdbc:mysql://192.168.10.13:3306/data </property> <property name="hibernate.connection.username">root</property> <property name="hibernate.connection.password">root</property> <property name="hibernate.connection.pool_size">10</property> <property name="show_sql">true</property> <property name="dialect">org.hibernate.dialect.MySQLDialect</property> <property name="hibernate.current_session_context_class">thread</property> </session-factory> </hibernate-configuration>
Output :
1. Data in a table Employee is as :
2. When you will execute the java file HibernateOrderByClause.java (RightClick -> run as -> Java Application) data of table employee will be displayed in console in the ascending order by name as :
