Book Image

Java Hibernate Cookbook

By : Yogesh Prajapati, Vishal Ranapariya
Book Image

Java Hibernate Cookbook

By: Yogesh Prajapati, Vishal Ranapariya

Overview of this book

This book will provide a useful hands-on guide to Hibernate to accomplish the development of a real-time Hibernate application. We will start with the basics of Hibernate, which include setting up Hibernate – the pre-requisites and multiple ways of configuring Hibernate using Java. We will then dive deep into the fundamentals of Hibernate such as SessionFactory, session, criteria, working with objects and criteria. This will help a developer have a better understanding of how Hibernate works and what needs to be done to run a Hibernate application. Moving on, we will learn how to work with annotations, associations and collections. In the final chapters, we will see explore querying, advanced Hibernate concepts and integration with other frameworks.
Table of Contents (15 chapters)
Java Hibernate Cookbook
About the Authors
About the Reviewers

Fetching an object from the database

Now we will take a look at how to fetch objects using a Session. Here, we will also see how to get only one record using the primary key column. We override a toString() method in the Employee and Department classes so that it's easy to display the data within an object, as shown in the following code:

    public String toString() {
      return "\nEmployee"
      + "\n id: " + this.getId()
      + "\n first name: " + this.getFirstName()
      + "\n salary: " + this.getSalary()
      + "\n department: " + this.getDepartment().getDeptName();

How to do it…

Here, we are trying to get an employee having id equals 1.

The equivalent SQL query is as follows:

SELECT * FROM employee WHERE id=1;

Now, let's look at how to do the same using hibernate:

  1. Enter the following code to fetch an object of the employee type, where the id is 1:

    SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
    Session session =  sessionFactory.openSession();