Hibernate is a great tool for ORM mappings in Java. It can cut down a lot of complexity and thus defects as well from your application, which may otherwise find a way to exist. This is specially boon for developers with limited knowledge of SQL. Hibernate Architecture The following diagram summarizes the main building blocks in hibernate architecture.
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Hibernate is a great tool for ORM mappings in Java. It can cut down a lot of complexity and thus defects as well from your application, which may otherwise find a way to exist.
This is specially boon for developers with limited knowledge of SQL. Hibernate Architecture The following diagram summarizes the main building blocks in hibernate architecture. Configuration : Generally written in hibernate. For Java configuration, you may find class annotated with Configuration. Session Factory : Any user application requests Session Factory for a session object. Session Factory uses configuration information from above listed files, to instantiates the session object appropriately.
Session : This represents the interaction between the application and the database at any point of time. This is represented by the org. Session class. The instance of a session can be retrieved from the SessionFactory bean. Query : It allows applications to query the database for one or more stored objects.
First-level cache : It represents the default cache used by Hibernate Session object while interacting with the database. It is also called as session cache and caches objects within the current session. All requests from the Session object to the database must pass through the first-level cache or session cache. One must note that the first-level cache is available with the session object until the Session object is live. Transaction : enables you to achieve data consistency, and rollback incase something goes unexpected.
Persistent objects : These are plain old Java objects POJOs , which get persisted as one of the rows in the related table in the database by hibernate. They can be configured in configurations files hibernate. Second-level cache : It is used to store objects across sessions.
This needs to be explicitly enabled and one would be required to provide the cache provider for a second-level cache. One of the common second-level cache providers is EhCache.
As a result, business logic is able to access and manipulate database entities via Java objects. It helps to speed up the overall development process by taking care of aspects such as transaction management, automatic primary key generation, managing database connections and related implementations, and so on.
JPA is a set of specifications for accessing, persisting, and managing data between Java objects and relational database entities. Idiomatic persistence Any class that follows object-oriented principles such as inheritance, polymorphism, and so on, can be used as a persistent class.
High performance and scalability Hibernate supports techniques such as different fetching strategies, lazy initialization, optimistic locking, and so on, to achieve high performance, and it scales well in any environment.
Easy to maintain Hibernate is easier to maintain as it requires no special database tables or fields. It generates SQL at system initialization time.
It is much quicker and easier to maintain compared to JDBC. In this page, I have categorized all available hibernate examples in this blog. This page will be updated every time, a new hibernate tutorial is published in this blog.
Stay Tuned!! Feel free to suggest topics you want to read more on. Hello world application In this post, I will try to detail out more information on hibernate and then will identify the basic steps to use hibernate for our first running java hibernate example application. Basic concepts How to build SessionFactory in hibernate 4 If you have been watching previous hibernate releases then you must have noticed that they have deprecated a lot of classes in quick succession.
In this hibernate tutorial, I am giving an example of building hibernate SessionFactory without using deprecated classes mentioned above. I am using the latest hibernate version i. Hibernate 4. Final, so you can make sure that you are using the latest approach for building session factory. Entities Equality and Identity Concepts Many times in our application, we face a situation where we have to compare two objects to check their equality for satisfying some business rules.
In core java, we have already much knowledge about checking equality of objects, but in hibernate, we need to take care of a few extra things as well. Defining Association Mappings between Hibernate Entities When we annotate the java classes with JPA annotations and make them persistent entities, we can face situations where two entities can be related and must be referenced from each other, in either uni-direction or in bi-direction.
Spring MVC Hibernate MySQL Integration CRUD Example Tutorial
Note that I have noticed that all spring and hibernate versions are not compatible, below versions have worked for me so I think they are compatible. If you are using some other versions and getting java. NoClassDefFoundError, then it means that they are not compatible. For example org. FilterDefinition class is moved to org.
Hibernate - ORM Overview
Important dependencies above are spring-context, spring-webmvc, spring-tx, hibernate-core, hibernate-entitymanager and spring-orm. I am using Apache Commons DBCP for connection pooling, but in real life situations, most probably you have connection pooling done by the container and all we need is to provide the JNDI reference details to use. NOTE: I noticed that some of the readers are getting database connection issues. Notice that in my pom. For any database connection related issues, either put the database driver in container lib or include that in pom.