Hibernate projection max, avg, min, count example

How do I use min, max, avg and sum Projections?

Category: org.hibernate, viewed: 7K time(s).

The code below demonstration the use of Projections.min(), Projections.max(), Projections.avg() and Projections.sum().

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package org.kodejava.example.hibernate.criteria;


 

import org.hibernate.SessionFactory;

import org.hibernate.Session;

import org.hibernate.HibernateException;

import org.hibernate.Criteria;

import org.hibernate.criterion.Projections;

import org.hibernate.cfg.AnnotationConfiguration;

import org.kodejava.example.hibernate.model.Track;


 

public class MinMaxAvgSumProjectionsDemo {

    private static final SessionFactory sessionFactory;


 

    static {

        try {

            sessionFactory = new AnnotationConfiguration().

                    configure("hibernate.cfg.xml").

                    buildSessionFactory();

        }

        catch (Throwable ex) {

            throw new ExceptionInInitializerError(ex);

        }

    }


 

    public static Session getSession() throws HibernateException {

        return sessionFactory.openSession();

    }


 

    public static void main(String[] args) {

        final Session session = getSession();

        try {

            Criteria criteria = session.createCriteria(Track.class)

                    .setProjection(Projections.max("duration"));

            Integer maxDuration = (Integer) criteria.uniqueResult();

            System.out.println("Max Track Duration = " + maxDuration);


 

            criteria.setProjection(Projections.min("duration"));

            Integer minDuration = (Integer) criteria.uniqueResult();

            System.out.println("Min Track Duration = " + minDuration);


             

            criteria.setProjection(Projections.avg("duration"));

            Double avgDuration = (Double) criteria.uniqueResult();

            System.out.println("Avg Track Duration = " + avgDuration);


             

            criteria.setProjection(Projections.sum("duration"));

            Integer totalDuration = (Integer) criteria.uniqueResult();

            System.out.println("Total Track Duration = " + totalDuration);

        } finally {

            session.close();

        }

    }

}