dineshonjava

Pagination in Hibernate Query Language (HQL)

In this tutorial of Pagination in Hibernate Query Language (HQL) we will discuss about the pagination query in hibernate for pulling specific number data with different pages. Pagination of search results is a common requirement for any application.

Out of performance reasons it is recommended to restrict the number of returned objects per query. In fact is a very common use case anyway that the user navigates from one page to an other. The way to define pagination is exactly the way you would define pagination in a plain HQL or Criteria query.

Using the createQuery() method of a Session object that returns a Query object. First, instantiate the Session object using the openSession() method of SessionFactory. Then, invoke the createQuery() method on the resulting object.

Query q = session.createQuery("...");
q.setFirstResult(start);
q.setMaxResults(length);

Student.java
package com.sdnext.hibernate.tutorial.dto;

import java.io.Serializable;

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

@Entity
@Table(name="STUDENT")
public class Student implements Serializable 
{
 /**
  * serialVersionUID
  */
 private static final long serialVersionUID = 8633415090390966715L;
 @Id
 @Column(name="ID")
 @GeneratedValue(strategy=GenerationType.AUTO)
 private int id;
 @Column(name="STUDENT_NAME")
 private String studentName;
 @Column(name="ROLL_NUMBER")
 private int rollNumber;
 @Column(name="COURSE")
 private String course;
 public int getId() {
  return id;
 }
 public void setId(int id) {
  this.id = id;
 }
 public String getStudentName() {
  return studentName;
 }
 public void setStudentName(String studentName) {
  this.studentName = studentName;
 }
 public int getRollNumber() {
  return rollNumber;
 }
 public void setRollNumber(int rollNumber) {
  this.rollNumber = rollNumber;
 }
 public String getCourse() {
  return course;
 }
 public void setCourse(String course) {
  this.course = course;
 }
 public String toString()
 {
  return "ROLL Number: "+rollNumber+"| Name: "+studentName+"| Course: "+course;
 }
}

hibernate.cfg.xml

<hibernate-configuration> 
 <session-factory> 
  <!-- Database connection settings -->
   <property name="connection.driver_class">com.mysql.jdbc.Driver</property> 
   <property name="connection.url">jdbc:mysql://localhost:3306/hibernateDB2</property> 
   <property name="connection.username">root</property> 
   <property name="connection.password">root</property> 

  <!-- JDBC connection pool (use the built-in) -->
   <property name="connection.pool_size">1</property> 

  <!-- SQL dialect -->
   <property name="dialect">org.hibernate.dialect.MySQLDialect</property> 

  <!-- Enable Hibernate's automatic session context management -->
    <property name="current_session_context_class">thread</property> 
  
  <!-- Disable the second-level cache -->
   <property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property> 

  <!-- Echo all executed SQL to stdout -->
   <property name="show_sql">true</property> 
  
  <!-- Drop and re-create the database schema on startup -->
   <property name="hbm2ddl.auto">update</property> 
   
   
   <mapping class="com.sdnext.hibernate.tutorial.dto.Student">
      
  </mapping></session-factory> 
 </hibernate-configuration>

HibernateTestDemo.java
package com.sdnext.hibernate.tutorial;

import java.util.List;

import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;

import com.sdnext.hibernate.tutorial.dto.Student;

public class HibernateTestDemo {
 /**
  * @param args
  */
 public static void main(String[] args) 
 {
  SessionFactory sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
  Session session = sessionFactory.openSession();
  session.beginTransaction();
  
  String SQL_QUERY = "FROM Student student";
  Query query = session.createQuery(SQL_QUERY);
  query.setFirstResult(1);//set first result start value
  query.setMaxResults(5);//number of result to be display
  
  List students = query.list();
  for(Student student : students)
  {
   System.out.println(student);
  }
  session.getTransaction().commit();
  session.close();
 }
}
Output:
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.annotations.Version).
log4j:WARN Please initialize the log4j system properly.
Hibernate: select student0_.ID as ID0_, student0_.COURSE as COURSE0_, student0_.ROLL_NUMBER as ROLL3_0_, student0_.STUDENT_NAME as STUDENT4_0_ from STUDENT student0_ limit ?, ?
ROLL Number: 2| Name: Sweety Rajput| Course: PGDCP
ROLL Number: 3| Name: Adesh Rajput| Course: MA
ROLL Number: 4| Name: DEV| Course: MA
ROLL Number: 5| Name: RAJ| Course: BA
ROLL Number: 6| Name: Pradeep| Course: BA

Pagination in Hibernate Query Language (HQL)


In the Next Chapter we will discuss about the Parameter Binding and SQL Injection.

              
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