Agenda What is Hibernate Overview Benefits Example Spring
Integration Benefits Example Questions
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What is Hibernate? Popular Open Source (LGPL) Object/Relational
Mapping (ORM) tool Transparent persistence for POJOs (Plain Old
Java Objects) Core of JBoss CMP 2.0 impl.
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Object/Relational Mapping JavaObject int id; String name;
String getName() int getId() void setName(String) void setId(int)
SQL Table id [int] primary key, name [varchar(50)] Magic Happens
Here (O/R Mapper i.e. Hibernate)
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Other ORM Solutions Open iBatis SQL Maps JDO Commercial
TopLink
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Why Hibernate? Retains natural object model (transparent)
Minimizes Code Does not require a container Model is not tied to
persistance implementation
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Hibernate's Goal Remove 95% of common data persistence
problems
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How do you use it? Act on your data model Query in SQL and/or
HQL... or using your object model
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Auction Object Model
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Persistant Class Default Constructor Getters/Setters
Collections use interface types Identifier property public class
AuctionItem { private Long _id; private Set _bids; private Bid
_successfulBid private String _description; public Long getId() {
return _id; } private void setId(Long id) { _id = id; } public
String getDescription() { return _description; } public void
setDescription(String desc) { _description=desc; } }
Working with Data Session session =
sessionFactory.openSession(); Transaction tx =
s.beginTransaction(); AuctionItem item = (AuctionItem)
session.get(ActionItem.class, itemId);
item.setDescription(newDescription); tx.commit(); session.close();
Retrieve an AuctionItem and change description
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Working with Data Retrieve an AuctionItem and create a new
persistent Bid Bid bid = new Bid(); bid.setAmount(bidAmount);
Session session = sf.openSession(); Transaction tx =
session.beginTransaction(); AuctionItem item = (AuctionItem)
session.get(ActionItem.class, itemId); bid.setItem(item);
item.getBids().add(bid); tx.commit(); session.close();
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Hibernate in code Retrieve an AuctionItem and create a new
persistent Bid Bid bid = new Bid(); bid.setAmount(bidAmount);
Session session = sf.openSession(); Transaction tx =
session.beginTransaction(); AuctionItem item = (AuctionItem)
session.get(ActionItem.class, itemId); bid.setItem(item);
item.getBids().add(bid); tx.commit(); session.close();
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Hibernate in code Retrieve an AuctionItem and create a new
persistent Bid Session session = sf.openSession(); Transaction tx =
session.beginTransaction(); AuctionItem item = (AuctionItem)
session.get(ActionItem.class, itemId); tx.commit();
session.close(); item.setDescription(newDescription); Session
session2 = sf.openSession(); Transaction tx =
session2.beginTransaction(); session2.update(item); tx.commit();
session2.close();
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Benefits Metadata controlled persistence Transparent - working
with the model, not the data access technology Pooling, Caching,
Transactions can all be handled outside of our code
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Integrating Spring and Hibernate
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Spring and Hibernate Benefits Examples
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Benefits Resource Management IoC / AOP Session Management
Extended Transaction Support JTA and/or JDBC Flexible Transaction
Demarcation Programmatic Declarative (Spring's XML config)
HibernateTemplate Simplifies Hibernate API
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Spring IoC Session POJO DAO setSession() save()
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Spring Interceptors (AOP) Business Logic getCatById() save(Cat)
DAOInterceptor Session Spring Framework
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Springs HibernateTemplate Hibernate Only: HibernateTemplate:
public User getUserByEmailAddress(final String email) { try {
Session session = sessionFactory.openSession(); List list =
session.find( "from User user where user.email=?", email,
Hibernate.STRING); return (User) list.get(0); } finally {
session.close(); } } public User getUserByEmailAddress(final String
email) { List list = getHibernateTemplate().find( "from User user
where user.email=?", email, Hibernate.STRING); return (User)
list.get(0); }
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News of the day (12/20/2004) Hibernate 3.0 Beta 1 released!
Features: Virtualization (Filters, Permissions, etc) New mapping
constructs HQL rewrite using ANTLR Representation Independence
i.e.HashMap Statistics and JMX Monitoring Stored Procedures /
Handwritten SQL Much more
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Important Links http://www.hibernate.org
http://www.hibernate.org http://www.springframework.org
http://www.springframework.org Parts of this presentation come from
documentation and presentations on the hibernate.org website:
http://www.hibernate.org/hib_docs/reference/en/pdf/hibernate_reference.pdfhttp://www.hibernate.org/hib_docs/reference/en/pdf/hibernate_reference.pdf
- Manual
http://www.hibernate.org/hib_docs/online/jaoo_presentation/HibernateJAOO.ppthttp://www.hibernate.org/hib_docs/online/jaoo_presentation/HibernateJAOO.ppt
- Presentation by Gavin King
http://www.hibernate.org/200.htmlhttp://www.hibernate.org/200.html
- Road Map Books: J2EE Development without EJB Rod Johnson and
Juergen Hoeller Better, Faster, Lighter Java Bruce A. Tate and
Justin Gehtland Hibernate in Action Christian Bauer and Gavin
King
