1	Modulo II Spring-JDBC Prof. Ismael H F Santos
2	Bibliografia Spring in Action Craig Walls and Ryan Breidenbach Professional Java Development with Spring Rod Johnson, Juergen Hoeller and Team Spring – www.springframework.org J2EE without EJB – Rod Johnson/ Jurgen Hoeller Better, Faster, Lighter Java – Bruce Tate Wiring your Web Application with Open Source Java http://www.onjava.com/pub/a/onjava/2004/04/07/wiringwebapps.html
3	Spring Related Tools and Add-Ons ACEGI Security - comprehensive security services for the Spring Framework Spring IDE - graphical user interface for the configuration files used by the Spring Framework Spring BeanDoc - tool that facilitates documentation and graphing of Spring bean factories and application context files XDoclet Spring Tags - support for generating Spring XML config files from annotations in Java classes (you could also use JDK1.5 annotations to achieve this) Spring Web Flow - for web applications with demanding page flow requirements AppFuse Not really a tool or add-on, but AppFuse is Matt Raible's project to jumpstart your Java web projects. It uses Spring at it's core and studying it is a great way to learn about Spring. Spring Framework .NET – Spring Clone for the Dark Side J
4	Spring Framework / Spring Related References The Official Spring Reference Manual http://www.springframework.org/docs/reference/ Introduction to Spring by Rod Johnson http://www.theserverside.com/articles/article.tss?l=SpringFramework Spring in Action by Craig Walls and Ryan Breidenbach Pro Spring by Rob Harrop and Jan Machacek J2EE Without EJB by Rod Johnson and Juergen Holler Expert One-on-One J2EE Design and Development by Rod Johnson Spring Developers Notebook by Bruce Tate and Justin Gehtland Better, Faster, Lighter Java by Bruce Tate and Justin Gehtland Spring Live by Matt Raible Professional Java Development with the Spring Framework by many of the core Spring developers: Coming in July 2005
5	Ementa Spring DAO Spring JDBC
6	WebApp
7	O que temos? Uma camada de abstração para persistência de dados utilizando um ou mais das seguintes tecnologias JDBC Hibernate, OJB JDO iBatis Uma robusta infra-estrutura para o gerenciamento de transações de forma declarativa que suporta tanto transações locais como transações distribuídas através da JTA Uma camada simplificadora para tecnologias de distribuição incluindo EJBs, RMI, e Web Services Útil suporte a JNDI, JMS, email, e agendamento de tarefas(task scheduling)
8	Spring DAO Possui uma API de acesso a dados que ajuda a isolar e melhorar o modo como o dado é servido pela camada de negócio Mais uma consistente e rica hierarquia de exceções suficiente para mapear exceções específicas dependentes de tecnologia para outras exceções genéricas Além de uma série de templates e warpper classes para se trabalhar com JDBC, Hibernate, JDO, etc.
9	Spring’s JDBC Api
10	JDBC Tradicional
11	Spring Transactions
12	Spring Transactions
13	Spring Transaction Consistent abstraction PlatformTransactionManager Does not reinvent transaction manager Choose between JTA, JDBC, Hibernate, JDO etc with simple changes to configuration not Java code No more rewriting application to scale up from JDBC or Hibernate local transactions to JTA global transactions Use the simplest transaction infrastructure that can possibly work Programmatic transaction management Simpler API than JTA Use the same API for JTA, JDBC, Hibernate etc. Write once have transaction management everywhere^TM
14	Declarative Transaction Management Most popular transaction management option Built on same abstraction as programmatic transaction management Declarative transaction management for any POJO, without EJB: even without JTA (single database) More flexible than EJB CMT Declarative rollback rules: roll back on MyCheckedException Non-invasive: Minimizes dependence on the container No more passing around EJBContext
15	Transações com Spring Suporte para gerenciamento programático e declarativo de transações Transações locais são delegadas pelo Spring para o gerente de transações do data-source Quando múltiplos recursos estão involvidos (transações distribuídas), Spring delega para o gerente de transações JTA obtido através do JNDI Apenas algumas pequenas mudanças são necessárias para trocar entre local e JTA
16	Transações com Spring Gerenciamento Declarativo (+) Usa AOP para encapsular chamadas a objetos transacionais com código de begin e commit de transações Comportamento de propagação Mandatory, Never, Not Supported, Required, Requires New, Support, Nested Similar a EJBs Também suporta níveis de isolação Default, Read Uncommitted, Read Committed, Repeatable Read, Serializable
17	Transações com Spring Declarando atributos
18	Transações com Spring
19	Transações com Spring
20	Make ServiceImpl POJO transactional public class ServiceImpl implements Service { private int timeout; private AccountDao accountDao; public void setTimeout(int timeout) { this.timeout = timeout; } public void setAccountDao(AccountDao accountDao) { this.accountDao = accountDao; } public void doSomething() throws ServiceWithdrawnException { } } <bean id="serviceTarget" class="com.mycompany.service.ServiceImpl"> <property name="timeout"><value>30</timeout></property> <property name="accountDao"><ref local="accountDao"/></property> </bean>
21	Make ServiceImpl transactional <bean id=“service" class=“org.springframework.transaction.interceptor.TransactionProxyFactoryBean"/> <property name="target"> <ref local="serviceTarget"/> </property> <property name="transactionManager"> <ref local="localTransactionManager"/> </property> <property name="transactionAttributes"> <props> <prop key="do*"> PROPAGATION_REQUIRED,-ServiceWithdrawnException </prop> </props> </property> </bean>
22	Make ServiceImpl transactional Rollback rule means that we don’t need to call setRollbackOnly() Of course Spring also supports programmatic rollback Can run this from a JUnit test case Doesn’t depend on a heavyweight container Can work with JTA, JDBC, Hibernate, JDO, iBATIS transactions… Just change definition of transaction manager
23	Make ServiceImpl transactional Alternative approaches, simpler in large applications: Use “auto proxy creator” to apply similar transaction attributes to multiple beans Use metadata or another pointcut approach to apply transactional behaviour to multiple classes
24	Spring DAO Integrated with Spring transaction management Unique synergy Gestalt again… Doesn’t reinvent the wheel. There are good solutions for O/R mapping, we make them easier to use Out-of-the-box support for JDBC Hibernate JDO iBATIS Model allows support for other technologies (TopLink etc) Consistent DataAccessException hierarchy allows truly technology-agnostic DAOs
25	Spring DAO: Consistent exception hierarchy
26	Consistent Abstract Classes for DAO Support Extend your DAO classes with the proper xxxDAOSupport class that matches your persistence mechanism. JdbcDaoSupport Super class for JDBC data access objects. Requires a DataSource to be set, providing a JdbcTemplate based on it to subclasses. HibernateDaoSupport Super class for Hibernate data access objects. Requires a SessionFactory to be set, providing a HibernateTemplate based on it to subclasses. JdoDaoSupport Super class for JDO data access objects. Requires a PersistenceManagerFactory to be set, providing a JdoTemplate based on it to subclasses. SqlMapDaoSupport Supper class for iBATIS SqlMap data access object. Requires a DataSource to be set, providing a SqlMapTemplate
27	Spring DAO Usando um template jdbc do spring
28	Spring DAO Operações também podem ser modeladas como objetos
29	Spring DAO Usando o objeto UpdateCustomer
30	Spring DAO Templates Built in code templates that support JDBC, Hibernate, JDO, and iBatis SQL Maps Simplifies data access coding by reducing redundant code and helps avoid common errors. Alleviates opening and closing connections in your DAO code. No more ThreadLocal or passing Connection/Session objects. Transaction management is handled by a wired bean You are dropped into the template with the resources you need for data access – Session, PreparedStatement, etc. Code only needs to be implemented in callback methods. doInXXX(Object) Optional separate JDBC framework
31	Ex: Code without a template public class OrderHibernateDAO implements IOrderDAO { public Order saveOrder(Order order) throws OrderException{ Session s = null; Transaction tx = null; try{ s = ... // get a new Session object tx = s.beginTransaction(); s.save(order); tx.commit(); } catch (HibernateException he){ // log, rollback, and convert to OrderException } catch (SQLException sqle){ // log, rollback, and convert to OrderException } finally { s.close(); // needs a try/catch block } return order; }
32	Ex: Spring DAO Template Example public class OrderHibernateDAO extends HibernateDaoSupport implements IOrderDAO { ... public Order saveOrder(final Order order) { HibernateTemplate hib = getHibernateTemplate(); return (Order)hib.execute(new HibernateCallback() { public Object doInHibernate(Session session) throws HibernateException, SQLException { session.save(order); return order; } }); } ... }
33	Ex 2: Spring DAO Template Example public class OrderHibernateDAO extends HibernateDaoSupport implements IOrderDAO { ... public List findOrdersByCustomerId(int id) { HibernateTemplate hib = getHibernateTemplate(); return hib.findByNamedQuery(“OrdersByCustomerID”, new Integer(id)); } public Order findOrderById(int orderId ) { HibernateTemplate hib = getHibernateTemplate(); return (Order) hib.load(Order.class, new Integer(orderId)); } ... }
34	Spring DAO: JDBC Class library offers simpler programming model than raw JDBC Two flavours of usage: Callbacks (JdbcTemplate) JDBC objects: Model queries, updates and stored procedures as objects No more try/catch/finally blocks No more leaked connections Spring will always close a connection: no scope for programmer error Meaningful exception hierarchy No more vendor code lookups Spring autodetects database and knows what Oracle, DB2 error codes mean More portable code More readable code catch (BadSqlGrammarException ex) Stored procedure support Can refactor to clean up JDBC without adopting Spring overall Incremental adoption: Step by step
35	Integração ao Hibernate Spring prove um bean SessionFactory que simplifica a configuração e o gerênciamento de sessões em objetos de negócio Uma classe HibernateTemplate Uma classe HibernateDaoSupport que pode ser herdada para maior abstração Gerenciamento e mapeamento das HibernateException´s Facilmente plugável ao framework de Transações do Spring
36	Integração ao Hibernate Exemplo de configuração
37	Integração ao Hibernate Exemplo de configuração (cont)
38	Integração ao Hibernate
39	Spring DAO: Hibernate Manages Hibernate sessions No more custom ThreadLocal sessions Sessions are managed within Spring transaction management Works with JTA if desired Works within EJB container with CMT if desired HibernateTemplate makes common operations easy Simpler, consistent exception handling Many operations become one-liners Less, simpler, code compared to using Hibernate alone Portability: Switch between Hibernate, JDO and other transparent persistence technologies without changing DAO interfaces Can even switch to JDBC where transparent update is not implied Mixed use of Hibernate and JDBC within the same transaction
40	HibernateTemplate DAO example public class MyHibernateDao implements MyDao { private HibernateTemplate hibernateTemplate; public MyHibernateDao (net.sf.hibernate.SessionFactory sessionFactory) { hibernateTemplate = new HibernateTemplate(sessionFactory); } public Collection getWorkflows() { return hibernateTemplate.find("from Workflow"); } <bean id="sessionFactory" class="org.springframework.orm.hibernate.LocalSessionFactoryBean"> <property name="dataSource"><ref local="dataSource"/></property> <property name="mappingResources"> <value>mycompany/mappings.hbm.xml</value> </property> <property name="hibernateProperties"> <props> <prop key="hibernate.dialect">net.sf.hibernate.dialect.HSQLDialect</prop> </props> </property> </bean> <bean id=“myDao" class=“com.mycompany.MyHibernateDao" autowire="constructor" >
41	Consistent Exception Handling Spring has it’s own exception handling hierarchy for DAO logic. No more copy and pasting redundant exception logic! Exceptions from JDBC, or a supported ORM, are wrapped up into an appropriate, and consistent, DataAccessException and thrown. This allows you to decouple exceptions in your business logic. These exceptions are treated as unchecked exceptions that you can handle in your business tier if needed. No need to try/catch in your DAO. Define your own exception translation by subclassing classes such as SQLErrorCodeSQLExceptionTranslator
42	Spring and Testing Easier test driven development (TDD) Integration testing Can use a standalone Spring configuration with mock objects for testing. Consider XMLApplicationContext or FileSystemApplicationContext. Unit testing Allows you to test outside the container without using the Spring container. Easy to test POJOs
43	Even More Spring Components JavaMail helpers Scheduling support via Quartz Convenience implementation classes for Remoting support – JAXRPC, RMI, Hessian, and Burlap EJB support for easier access. Acegi Security System for Spring http://acegisecurity.sourceforge.net/ Very good framework! Eclipse Plugin – Spring IDE for Eclipse Coming soon JMS implementation classes JMX support