I got into Hibernate because I'm lazy. Specifically, I got tired of writing my own systems to bridge my Java applications and relational databases. I write both Swing and server-based applications; I can't assume (nor do I enjoy) the complexity of EJB container-managed persistence. I hate writing SQL when all I really want to do is write Java code. I really don't like writing endless pages of mindless code, loading my JDBC results into Java objects and back.
Simply put, Hibernate solves all of these problems for me, and it does so in a fast, flexible manner. I can use it with Swing, JSP, or as an EJB BMP solution. I can test my code outside of a container. I can even use it to manage my database schema.
Regardless of your background—whether you are a nothing-but-JDBC developer or a full EJB-level architect—you can save yourself considerable time and effort by adding Hibernate to your skill set, and in the process you can get a significant leg up on learning EJB 3.0. You can learn the principal terminology and concepts behind EJB 3.0 today, on the Java 2 (JDK 1.4) JVM you are using now.
Life is short. Spend less time writing code that bridges your database and your Java application and more time adding new features.
Familiarity with Java development, including objectoriented design. If you don't already know Java, this book will be quite unhelpful.
Familiarity with SQL and relational databases. There are many books on both the practical and theoretical sides of relational database design and development. The examples in this book are all done with MySQL, a free, open-source database. If you have never worked with a relational database before, you will almost certainly want to pick up an introductory text on MySQL.
Familiarity with Ant. Many books on Ant are available; if you are a Java developer and haven't already worked with Ant, you should learn.
Other skills, such as familiarity with JSP web application development, are helpful but not required. One example in Chapter 2 assumes the use of a web server such as Tomcat—all other examples can be run from the command-line.
This book can be loosely broken into a few basic sections. Following the introductory chapter, Chapters 2 through 4 illustrate different approaches to Hibernate development: starting from a Hibernate object/relational mapping file, starting from Java code, or starting from an existing database schema. Chapters 5 through 12 cover basic concepts and the use of persistent objects, concluding with chapters on tools, performance, and best practices. Chapter 13 discusses the future of Hibernate.
This book can be read in several ways, depending on your inclination. If you wish to start with real-world examples and then move into general usage and theory, you can more or less read the book in order. If you prefer a higher-level introduction, you may wish to start with Chapters 6 through 9 and then return to the beginning. Regardless of the method you choose, I encourage you to download and work through the examples from http://www.cascadetg.com/hibernate/.
Chapter 1 introduces Hibernate. It compares Hibernate to other forms of database access, including JDBC and a variety of other tools. It concludes with a list of required files and where to obtain them.
Chapter 2 illustrates an example of development starting with a Hibernate mapping file. The mapping file is used to generate Java and database schema files.
Chapter 3 shows how to use Hibernate when starting from a Java source file. XDoclet is used to generate the mapping file, and Hibernate is used to generate the database schema.
Chapter 4 shows how to use Middlegen in conjunction with Hibernate when starting from an existing database schema.
Chapter 5 is a reference to the Hibernate mapping file format. While few readers will want to read this chapter from start to finish, this reference will hopefully prove invaluable on a day-to-day basis when using Hibernate.
Chapter 6 contains information on the general use of Hibernate, including basic operations such as creating, finding, refreshing, updating, and deleting objects.
Chapter 7 explains how Hibernate handles both class and database relationship concepts.
Chapter 8 discusses Hibernate's two main query mechanisms, HQL and Criteria, and also shows how native SQL can be integrated.
Chapter 9 covers the various aspects of a Hibernate transaction, illustrating both session and database transaction concepts.
Chapter 10 shows tools for identifying potential Hibernate performance issues.
Chapter 11 discusses how Hibernate can be used to manage an application's schema.
Chapter 12 covers various Hibernate best practices.
Chapter 13 discusses future directions for Hibernate, and also covers potential similarities with EJB 3.0.