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Examples
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Examples [cont'd]
How to map using @ElementCollection JPA annotation with Embeddable using Spring and Hibernate framework? @ElementCollection with @JoinTable, @GenericGenerator and @CollectionId using JPA Spring and Hibernate JPA @ElementCollection annotation with fetchtype eager and lazy in Spring Hibernate Framework How to do One to One mapping in JPA annotations with Spring Hibernate Framework How to do One to Many mapping in JPA annotations using Spring Hibernate Framework How to do Many to Many mapping in JPA annotations using Spring Hibernate Framework How to enable One to Many with CascadeType PERSIST using Spring Hibernate Framework
Examples [cont'd]
How to use JPA Entity with Inheritance using Spring Hibernate Framework How to use JPA Entity with inheritance single table strategy in Spring Hibernate Framework How to use JPA @Inheritance with InheritanceType.TABLE_PER_CLASS strategy in Spring Hibernate Framework How to use JPA @Inheritance with InheritanceType.JOINED strategy in Spring Hibernate Framework How to do CRUD actions using LocalContainerEntityManagerFactoryBean with JPA Spring Hibernate Framework How to use Hibernate Query Language(HQL) with Hibernate Spring Framework How to do Pagination and Fetching selected columns in Hibernate Queries with Spring Hibernate Framework
Examples [cont'd]
How to bind where clause parameters in Query Object in JPA Spring Hibernate How to use NamedNativeQuery and NamedQuery of JPA with Spring and Hibernate Framework How to use CriteriaQuery and CriteriaBuilder of EntityManager in JPA Spring Hibernate Framework What is Query Cache (First level cache) in JPA Spring Hibernate Frameworks How to configure Second Level Cache (EhCacheRegionFactory) with JPA Spring Hibernate FrameWork
How to do Pagination and Fetching selected columns in Hibernate Queries with Spring Hibernate Framework
4022 Views
Hints 
Pagination Limit setting with setFirstResult and setMaxResults methods of Hibernate on SELECT Queries.
  • setFirstResult used to set starting index.
  • setMaxResults used to set no of results in the query.
Fetching selected columns in HQL by defining constructors in HQL Queries.

Example
SELECT new STUDENT_INFO(studentId,StudentName) FROM STUDENT_INFO
Output: Browser 
Project Explorer Preview 
StudentInfo.java
package com.knowledgewalls.entity;

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

@Entity(name="STUDENT_INFO")
public class StudentInfo {
    @Id @GeneratedValue(strategy=GenerationType.AUTO)
    @Column(name="STUDENT_ID")
    private int studentId;
    
    @Column(name="STUDENT_NAME")
    private String StudentName;
    
    public StudentInfo(){}
    
    public StudentInfo(int studentId,String StudentName){
        this.studentId = studentId;
        this.StudentName = StudentName;
    }
    
    public int getStudentId() {
        return studentId;
    }
    public void setStudentId(int studentId) {
        this.studentId = studentId;
    }

    public String getStudentName() {
        return StudentName;
    }
    public void setStudentName(String studentName) {
        StudentName = studentName;
    }
}
StudentInfoDAO.java
package com.knowledgewalls.dao;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.persistence.Query;

import org.springframework.stereotype.Repository;
import org.springframework.transaction.annotation.Transactional;

import com.knowledgewalls.entity.StudentInfo;

@Repository
@Transactional
public class StudentInfoDAO {
    
    @PersistenceContext
    EntityManager em;
    
    public void save10Students(){
        try {
            for (int i=1;i<=10;i++){
                StudentInfo studentInfo = new StudentInfo();
                    studentInfo.setStudentName("Student "+i);
                        
                em.persist(studentInfo);
            }
        }
        catch(Exception e){
            System.out.println("Insertion Failure.");
            e.printStackTrace();
        }
    }
    
    public List<StudentInfo> getFirstFive(){
        try {
            Query query = em.createQuery("from STUDENT_INFO");
            
            //starts at first row
            query.setFirstResult(1);
            
            //takes 5 records
            query.setMaxResults(5);
            
            return query.getResultList();
        }
        catch (Exception e){
            e.printStackTrace();
            return new ArrayList<StudentInfo>();
        }
    }
    
    public List<String> getStudentNames(){
        try {
            Query query = em.createQuery("SELECT StudentName FROM STUDENT_INFO");
            return query.getResultList();
        }
        catch (Exception e){
            e.printStackTrace();
            return new ArrayList<String>();
        }
    }
    
    public List<Map<String,String>> getStudentNamesAsMap(){
        try {
            Query query = em.createQuery("SELECT new map(studentId,StudentName) FROM STUDENT_INFO");
            return query.getResultList();
        }
        catch (Exception e){
            e.printStackTrace();
            return new ArrayList<Map<String,String>>();
        }
    }
    
    public List<Object[]> getStudentNamesWithDesired(){
        try {
            Query query = em.createQuery("SELECT studentId,StudentName FROM STUDENT_INFO");
            return query.getResultList();
        }
        catch (Exception e){
            e.printStackTrace();
            return new ArrayList<Object[]>();
        }
    }
    
    public List<StudentInfo> getStudentNamesWithEntityObject(){
        try {
            Query query = em.createQuery("SELECT new STUDENT_INFO(studentId,StudentName) FROM STUDENT_INFO");
            return query.getResultList();
        }
        catch (Exception e){
            e.printStackTrace();
            return new ArrayList<StudentInfo>();
        }
    }
}
StudentInfoController.java
package com.knowledgewalls.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;

import com.google.gson.Gson;
import com.knowledgewalls.dao.StudentInfoDAO;

@Controller
public class StudentInfoController {
    
    @Autowired
    StudentInfoDAO studentInfoDAO;
    
    private void displayObject(Object object) {
        System.out.println(new Gson().toJson(object));
    }
    
    @RequestMapping(value="/addStudent",method=RequestMethod.GET)
    public @ResponseBody String addUsers(){
        {
            studentInfoDAO.save10Students();
            displayObject(studentInfoDAO.getFirstFive());
            displayObject(studentInfoDAO.getStudentNames());
            displayObject(studentInfoDAO.getStudentNamesAsMap());
            displayObject(studentInfoDAO.getStudentNamesWithDesired());
            displayObject(studentInfoDAO.getStudentNamesWithEntityObject());
        }
        
        return "Saved and Retrieved by HQL";
        
    }
}
Persistence.xml
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd" >

  <persistence-unit name="hibernatePersistenceUnit">
          <properties>
            <property name="hibernate.hbm2ddl.auto" value="create" />
        </properties>
  </persistence-unit>

</persistence>
Beans-servlet.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:p="http://www.springframework.org/schema/p"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
        http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-3.0.xsd">

    <context:component-scan base-package="com.knowledgewalls" />
    <mvc:annotation-driven />
    <tx:annotation-driven transaction-manager="transactionManager" />
    
    <bean id="emf" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="persistenceXmlLocation" value="classpath*:persistence.xml" />
        <property name="persistenceUnitName" value="hibernatePersistenceUnit" />
        <property name="dataSource" ref="dataSource"/>
        <property name="jpaVendorAdapter" ref="jpaVendorAdapter"/>
    </bean>
    
    <bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/test" />
        <property name="username" value="root" />
        <property name="password" value="mysql" />
        <property name="initialSize" value="5" />
        <property name="maxActive" value="10" />
    </bean>
    
    <bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
        <property name="database" value="MYSQL"></property>
        <property name="showSql" value="true"></property>
        <property name="generateDdl" value="false"></property>
        <property name="databasePlatform" value="org.hibernate.dialect.MySQL5InnoDBDialect"></property>
    </bean>
    
    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
         <property name="entityManagerFactory" ref="emf" />
    </bean>
    
    <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter" />
    <bean class="org.springframework.orm.jpa.support.PersistenceAnnotationBeanPostProcessor"/>
    <bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>

</beans>
Web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>Hibernate021_PaginationNSelectedColumns</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
 
  <servlet>
    <servlet-name>beans</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>beans</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>
Output: SQL
create table STUDENT_INFO
(STUDENT_ID integer not null auto_increment,
STUDENT_NAME varchar(255),
primary key (STUDENT_ID)) ENGINE=InnoDB;
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