How do I set the fetch mode for Criteria association?

By Wayan in Hibernate 0 Comment

o set the fetching mode for association we can call the Criteria‘s setFetchMode() method. We can use the FetchMode.SELECT or FetchMode.JOIN.

package org.kodejava.hibernate;

import org.hibernate.*;
import org.hibernate.cfg.Configuration;
import org.hibernate.criterion.Restrictions;
import org.kodejava.hibernate.model.Record;

import java.util.List;

public class FetchModeDemo {
    public static Session getSession() throws HibernateException {
        String cfg = "hibernate.cfg.xml";
        SessionFactory sessionFactory = new Configuration().configure(cfg)
                .buildSessionFactory();
        return sessionFactory.openSession();
    }

    @SuppressWarnings("unchecked")
    public static void main(String[] args) {
        try (Session session = getSession()) {
            Criteria criteria = session.createCriteria(Record.class)
                    .setFetchMode("artist", FetchMode.SELECT)
                    .setFetchMode("label", FetchMode.SELECT)
                    .add(Restrictions.like("title", "The Beatles%"));

            List<Record> records = criteria.list();
            for (Record record : records) {
                System.out.println("Recording  = "
                        + record.getTitle());
                System.out.println("Artist     = "
                        + record.getArtist().getName());
            }
        }
    }
}

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>5.6.9.Final</version>
    </dependency>
    <dependency>
        <groupId>com.mysql</groupId>
        <artifactId>mysql-connector-j</artifactId>
        <version>8.0.33</version>
    </dependency>
</dependencies>

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How do I count the total records using Projections?

By Wayan in Hibernate 4 Comments

The example below show how to get total row count using the Projections.rowCount(). The result of this query will be a single object of Integer that contains the result of executing an SQL select count (*) command.

package org.kodejava.hibernate;

import org.hibernate.SessionFactory;
import org.hibernate.Session;
import org.hibernate.HibernateException;
import org.hibernate.Criteria;
import org.hibernate.cfg.Configuration;
import org.hibernate.criterion.Projections;
import org.kodejava.hibernate.model.Track;

import java.util.List;

public class ProjectionsCountDemo {
    public static Session getSession() throws HibernateException {
        String cfg = "hibernate.cfg.xml";
        SessionFactory sessionFactory = new Configuration().configure(cfg)
                .buildSessionFactory();
        return sessionFactory.openSession();
    }

    @SuppressWarnings("unchecked")
    public static void main(String[] args) {
        try (Session session = getSession()) {
            Criteria criteria = session.createCriteria(Track.class)
                    .setProjection(Projections.rowCount());

            List<?> result = criteria.list();
            if (!result.isEmpty()) {
                Long rowCount = (Long) result.get(0);
                System.out.println("Total records: " + rowCount);
            }
        }
    }
}

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>5.6.9.Final</version>
    </dependency>
    <dependency>
        <groupId>com.mysql</groupId>
        <artifactId>mysql-connector-j</artifactId>
        <version>8.0.33</version>
    </dependency>
</dependencies>

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How do I order the Criteria query result set?

By Wayan in Hibernate 0 Comment

In this demo you’ll see how to order the result set of out Criteria query. It can be done by adding the org.hibernate.criterion.Order into the Criteria object, and we can either order the result in ascending or descending order.

package org.kodejava.hibernate;

import org.hibernate.SessionFactory;
import org.hibernate.Session;
import org.hibernate.HibernateException;
import org.hibernate.Criteria;
import org.hibernate.cfg.Configuration;
import org.hibernate.criterion.Order;
import org.kodejava.hibernate.model.Track;

import java.util.List;

public class CriteriaOrderDemo {
    public static Session getSession() throws HibernateException {
        String cfg = "hibernate.cfg.xml";
        SessionFactory sessionFactory = new Configuration().configure(cfg)
                .buildSessionFactory();
        return sessionFactory.openSession();
    }

    @SuppressWarnings("unchecked")
    public static void main(String[] args) {
        try (Session session = getSession()) {
            Criteria criteria = session.createCriteria(Track.class)
                    .addOrder(Order.asc("title"))
                    .setFirstResult(0)
                    .setMaxResults(10);

            List<Track> tracks = criteria.list();
            for (Track track : tracks) {
                System.out.println("Track = " + track.getTitle());
            }
        }
    }
}

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>5.6.9.Final</version>
    </dependency>
    <dependency>
        <groupId>com.mysql</groupId>
        <artifactId>mysql-connector-j</artifactId>
        <version>8.0.33</version>
    </dependency>
</dependencies>

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How do I add Restrictions to the Criteria object?

By Wayan in Hibernate 0 Comment

In this example you’ll learn how to add restrictions to the Criteria object. Using restriction we can narrow the result of our query. In the code below we add some restrictions such as Restrictions.eq(), Restrictions.like() and Restrictions.isNotNull().

In Hibernate framework you’ll find a lot of class the use a method chaining. As in the example below you can see that we actually can add an endless restrictions by calling the add() method.

package org.kodejava.hibernate;

import org.hibernate.SessionFactory;
import org.hibernate.Session;
import org.hibernate.HibernateException;
import org.hibernate.Criteria;
import org.hibernate.criterion.Restrictions;
import org.hibernate.cfg.Configuration;
import org.kodejava.hibernate.model.Track;

import java.util.List;

public class RestrictionsDemo {
    public static Session getSession() throws HibernateException {
        String cfg = "hibernate.cfg.xml";
        SessionFactory sessionFactory = new Configuration().configure(cfg)
                .buildSessionFactory();
        return sessionFactory.openSession();
    }

    @SuppressWarnings("unchecked")
    public static void main(String[] args) {
        try (Session session = getSession()) {
            Criteria criteria = session.createCriteria(Track.class)
                    .createAlias("artist", "artist")
                    .createAlias("genre", "genre")
                    .add(Restrictions.eq("title", "Ob-La-Di, Ob-La-Da"))
                    .add(Restrictions.like("artist.name", "%Beatles%"))
                    .add(Restrictions.isNotNull("genre.name"));

            List<Track> tracks = criteria.list();
            for (Track track : tracks) {
                System.out.println("Track = " + track.getTitle() +
                        "; Artist = " + track.getArtist().getName() +
                        "; Genre = " + track.getGenre().getName());
            }
        }
    }
}

Here are some other restrictions that can also be used to narrow our Criteria query result, for a complete restrictions you can see the Restrictions class documentation.

  • Restrictions.ne("title", "Twist and Shout") – Apply a “not equal” constraint to the named property.
  • Restrictions.ilike("title", "Twist%") – A case-insensitive “like”.
  • Restrictions.isNull("title") – Apply an “is null” constraint to the named property.
  • Restrictions.gt("duration", new Integer(200)) – Apply a “greater than” constraint to the named property.
  • Restrictions.between("duration", new Integer(100), new Integer(200)) – Apply a “between” constraint to the named property
  • Restrictions.or(criterionA, criterionB) – Return the disjunction of two expressions.
  • Restrictions.disjuction() – Group expressions together in a single disjunction.

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>5.6.9.Final</version>
    </dependency>
    <dependency>
        <groupId>com.mysql</groupId>
        <artifactId>mysql-connector-j</artifactId>
        <version>8.0.33</version>
    </dependency>
</dependencies>

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How do I create a pagination using Criteria?

By Wayan in Hibernate 0 Comment

To create a pagination or limit the result set returned by the Criteria query we can use the setFirstResult() and setMaxResults() method. The setFirstResult() method defines the first row to start with and the setMaxResults() method defines the maximum number of records to read. Let’s see the demo below.

package org.kodejava.hibernate;

import org.hibernate.SessionFactory;
import org.hibernate.Session;
import org.hibernate.HibernateException;
import org.hibernate.Criteria;
import org.hibernate.cfg.Configuration;
import org.kodejava.hibernate.model.Track;

import java.util.List;

public class CriteriaPagingDemo {
    public static Session getSession() throws HibernateException {
        String cfg = "hibernate.cfg.xml";
        SessionFactory sessionFactory = new Configuration().configure(cfg)
                .buildSessionFactory();
        return sessionFactory.openSession();
    }

    @SuppressWarnings("unchecked")
    public static void main(String[] args) {
        try (Session session = getSession()) {
            Criteria criteria = session.createCriteria(Track.class);

            // Set the first record index to read from the result set.
            criteria.setFirstResult(0);
            // Set the maximum number of records to read
            criteria.setMaxResults(10);

            List<Track> tracks = criteria.list();
            for (Track track : tracks) {
                System.out.println("Track = " + track.getTitle());
            }
        }
    }
}

Maven Dependencies

<dependencies>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-core</artifactId>
        <version>5.6.9.Final</version>
    </dependency>
    <dependency>
        <groupId>com.mysql</groupId>
        <artifactId>mysql-connector-j</artifactId>
        <version>8.0.33</version>
    </dependency>
</dependencies>

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