What’s New in Spring 3.1

What’s New in Spring 3.1

New in Spring 3.0

• Java 5+
• Spring Expression Language
• New Spring MVC Features
• REST
• Ajax
• Declarative Validation
• Backwards compatible with Spring 2.5

Spring Expression Language

• Unified EL++
• Deferred evaluation of expressions
• Support for expressions that can set values and invoke methods
• Pluggable API for resolving Expressions
• Unified Expression Language: http://is.gd/2xqF
• Spring 3.0 allows usage in XML files and @Value annotations

REST Support

REST with @PathParam

http://myserver/myapp/show/123

@RequestMapping(method = RequestMethod.GET)

public User show(@PathParam Long id) {

return userManager.getUser(id);

}

REST with RestController

@Controller

public class ResumesController implements RestController<Resume, Long> {

GET http://myserver/myapp/resumes

public List<Resume> index() {}

POST http://myserver/myapp/resumes

public void create(Resume resume) {}

GET http://myserver/myapp/resumes/1

public Resume show(Long id) {}

DELETE http://myserver/myapp/resumes/1

public void delete(Long id) {}

PUT http://myserver/myapp/resumes/1

public void update(Resume resume) {}

}

Dropping Support For...

• Commons Attributes
• TopLink (EclipseLink instead)
• MVC Controller hierarchy
• Unit 3.8 Test classes

What’s New in Spring 3.1

• Java 7 Support
• Hibernate 4 Support
• Servlet 3.0 Support
• Cache Abstraction
• Java Configuration
• Environments and Profiles
• Test Context Support for Configuration Classes and Profiles

Java 7 Support

• Fork/join support
• JDBC 4.1
• Try-with-resources
• RowSet 1.1
• Multicatch and final rethrow
• String in switch statement support

What’s New in Hibernate 4?

• Move to Gradle for builds
• SessionFactory building
• Initial osgi-fication
• Java 6 / JDBC 4 as baseline
• Multi-tentant database support
• Migration to i18n logging framework

Hibernate 3

<bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>

<!-- Hibernate SessionFactory -->

<bean id="sessionFactory"

class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">

<property name="dataSource" ref="dataSource"/>

<property name="configLocation" value="classpath:hibernate.cfg.xml"/>

<property name="hibernateProperties">

<value>

hibernate.dialect=${hibernate.dialect}

hibernate.query.substitutions=true 'Y', false 'N'

hibernate.cache.use_second_level_cache=true

hibernate.cache.provider_class=org.hibernate.cache.EhCacheProvider

</value>

<!-- Turn batching off for better error messages under PostgreSQL -->

<!-- hibernate.jdbc.batch_size=0 -->

</property>

</bean>

<!-- Transaction manager for a single Hibernate SessionFactory (alternative to JTA) -->

<bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">

<property name="sessionFactory" ref="sessionFactory"/>

</bean>

Hibernate 4

<bean class="org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor"/>

<bean id="hibernateExceptionTranslator"

class="org.springframework.orm.hibernate4.HibernateExceptionTranslator"/>

<!-- Hibernate SessionFactory -->

<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">

<property name="dataSource" ref="dataSource"/>

<property name="configLocation" value="classpath:hibernate.cfg.xml"/>

<property name="hibernateProperties">

<value>

hibernate.dialect=${hibernate.dialect}

hibernate.query.substitutions=true 'Y', false 'N'

hibernate.cache.use_second_level_cache=true

hibernate.cache.provider_class=org.hibernate.cache.EhCacheProvider

</value>

<!-- Turn batching off for better error messages under PostgreSQL -->

<!-- hibernate.jdbc.batch_size=0 -->

</property>

</bean>

<!-- Transaction manager for a single Hibernate SessionFactory (alternative to JTA) -->

<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">

<property name="sessionFactory" ref="sessionFactory"/>

</bean>

Spring + Hibernate 3

@Autowired

@Required

public void setSessionFactory(SessionFactory sessionFactory) {

this.sessionFactory = sessionFactory;

this.hibernateTemplate = new HibernateTemplate(sessionFactory);

}

public List<T> getAll() {

return hibernateTemplate.loadAll(this.persistentClass);

}

public T get(PK id) {

T entity = hibernateTemplate.get(this.persistentClass, id);

if (entity == null) {

log.warn("Uh oh, '" + this.persistentClass + "' object with id '" + id + "' not found...");

throw new ObjectRetrievalFailureException(this.persistentClass, id);

}

return entity;

}

public T save(T object) {

return hibernateTemplate.merge(object);

}

public void remove(PK id) {

hibernateTemplate.delete(this.get(id));

}

Hibernate 4

@Autowired

@Required

public void setSessionFactory(SessionFactory sessionFactory) {

this.sessionFactory = sessionFactory;

}

public List<T> getAll() {

return sessionFactory.getCurrentSession().createQuery("from " + this.persistentClass).list();

}

public T get(PK id) {

T entity = (T) sessionFactory.getCurrentSession().get(this.persistentClass, id);

if (entity == null) {

log.warn("Uh oh, '" + this.persistentClass + "' object with id '" + id + "' not found...");

throw new ObjectRetrievalFailureException(this.persistentClass, id);

}

return entity;

}

public T save(T object) {

return (T) sessionFactory.getCurrentSession().merge(object);

}

public void remove(PK id) {

sessionFactory.getCurrentSession().delete(this.get(id));

}

JPA with Spring 2.0

JPA with Spring 3.1

Spring Data

Spring Data makes it easier to build Spring-powered applications that use new data access technologies such as non-relational databases, map-reduce frameworks, and cloud based data services as well as provide improved support for relational database technologies.

http://www.springsource.org/spring-data 

Plain JPA :: Before

/**

* Service interface for {@link Customer}s.

*

* @author Oliver Gierke

*/

public interface CustomerService {

Customer findById(Long id);

Customer save(Customer customer);

List<Customer> findAll();

List<Customer> findAll(int page, int pageSize);

List<Customer> findByLastname(String lastname, int page, int pageSize);

}

/**

* Plain JPA implementation of {@link CustomerService}.

*

* @author Oliver Gierke

*/

@Repository

@Transactional(readOnly = true)

public class CustomerServiceImpl implements CustomerService {

@PersistenceContext

private EntityManager em;

@Override

public Customer findById(Long id) {

return em.find(Customer.class, id);

}

@Override

public List<Customer> findAll() {

return em.createQuery("select c from Customer c", Customer.class).getResultList();

}

@Override

@Transactional

public Customer save(Customer customer) {

if (customer.getId() == null) {

em.persist(customer);

return customer;

} else {

return em.merge(customer);

}

}

JPA with Spring Data :: After

/**

* Repository to manage {@link Customer} instances.

*

* @author Oliver Gierke

*/

public interface CustomerRepository extends

CrudRepository<Customer, Long>, JpaSpecificationExecutor<Customer> {

Page<Customer> findByLastname(String lastname, Pageable pageable);

}

What’s New in Servlet 3.0

• Programmatic definition of filters, servlets, listeners and URL patterns
• @WebServlet, @WebFilter, @WebListener
• @WebInitParam
• @MultipartConfig
• Web Fragments
• Asynchronous Servlet and Comet Support

Hardest thing about Servlet 3?

Is getting the Maven dependency right ...

<!-- Servlet 3.0 -->

<!-- http://stackoverflow.com/questions/1979957/maven-dependency-for-servlet-3-0-api -->

<dependency>

<groupId>org.glassfish</groupId>

<artifactId>javax.servlet</artifactId>

<version>3.0</version>

<scope>provided</scope>

</dependency>

Spring + Servlet 3.0

• WebApplicationInitializer for programmatic configuration
• Instead of:

<servlet>

<servlet-name>kickstart</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>kickstart</servlet-name>

<url-pattern>*.htm</url-pattern>

</servlet-mapping>

Servlet 3.0

• WebApplicationInitializer for programmatic configuration
• You use:

import org.springframework.web.WebApplicationInitializer;

import org.springframework.web.servlet.DispatcherServlet;

import javax.servlet.ServletContext;

import javax.servlet.ServletRegistration;

public class KickstartWebAppInitializer implements WebApplicationInitializer {

@Override

public void onStartup(ServletContext container) {

ServletRegistration.Dynamic dispatcher =

container.addServlet("dispatcher", new DispatcherServlet());

dispatcher.setLoadOnStartup(1);

dispatcher.addMapping("*.htm");

}

}

• WebApplicationInitializer with XmlApplicationContext

import org.springframework.web.WebApplicationInitializer;

import org.springframework.web.context.support.XmlWebApplicationContext;

import org.springframework.web.servlet.DispatcherServlet;

import javax.servlet.ServletContext;

import javax.servlet.ServletRegistration;

public class KickstartWebAppInitializer implements WebApplicationInitializer {

@Override

public void onStartup(ServletContext container) {

XmlWebApplicationContext appContext = new XmlWebApplicationContext();

appContext.setConfigLocation("/WEB-INF/applicationContext.xml");

ServletRegistration.Dynamic dispatcher =

container.addServlet("dispatcher", new DispatcherServlet());

dispatcher.setLoadOnStartup(1);

dispatcher.addMapping("*.htm");

}

}

• WebApplicationInitializer with JavaConfig

public class KickstartWebAppInitializer implements WebApplicationInitializer {

@Override

public void onStartup(ServletContext container) {

// Create the 'root' Spring application context

AnnotationConfigWebApplicationContext rootContext =

new AnnotationConfigWebApplicationContext();

rootContext.register(AppConfig.class);

// Manage the lifecycle of the root application context

container.addListener(new ContextLoaderListener(rootContext));

// Create the dispatcher servlet's Spring application context

AnnotationConfigWebApplicationContext dispatcherContext =

new AnnotationConfigWebApplicationContext();

dispatcherContext.register(DispatcherConfig.class);

// Register and map the dispatcher servlet

ServletRegistration.Dynamic dispatcher =

container.addServlet("dispatcher",

new DispatcherServlet(dispatcherContext));

dispatcher.setLoadOnStartup(1);

dispatcher.addMapping("/");

}

}

@MVC Resources

<!-- View Resolver for JSPs -->

<beans:bean id="viewResolver"

class="org.springframework.web.servlet.view.InternalResourceViewResolver">

<beans:property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>

<beans:property name="prefix" value="/WEB-INF/pages/"/>

<beans:property name="suffix" value=".jsp"/>

</beans:bean>

<beans:bean id="messageSource"

class="org.springframework.context.support.ResourceBundleMessageSource">

<beans:property name="basename" value="messages"/>

<beans:property name="useCodeAsDefaultMessage" value="true"/>

</beans:bean>

<context:component-scan base-package="spring.kickstart"/>

<!-- Enables the Spring MVC @Controller programming model -->

<annotation-driven/>

<resources mapping="/resources/**" location="/resources/"/>

<!-- Maps '/' requests to the 'index' view -->

<view-controller path="/" view-name="index"/>

<link rel="stylesheet" type="text/css"

href="${ctx}/resources/styles/deliciouslyblue/theme.css" title="default" />

<link rel="alternate stylesheet" type="text/css"

href="${ctx}/resources/styles/deliciouslygreen/theme.css" title="green" />

<script type="text/javascript" src="http://code.jquery.com/jquery-1.7.1.min.js"></script>

<script type="text/javascript" src="${ctx}/resources/scripts/application.js"></script>

Web Performance Best Practices

• Optimizing caching
• Minimizing round-trip times
• Minimizing request overhead
• Minimizing payload size
• Optimizing browser rendering
• Optimizing for mobile

Wro4j

• Open Source Java project for optimization of web resources
• Provides concatenation and minimization of JS and CSS 
• Gzip, YUI Compressor, JsHint, JsHint, CssLint, LESS, SASS, CoffeeScript, Dojo Shrinksafe

Profiles

XML Profiles

• Profiles allow for environment-specific bean definitions
• Activated with:
• -Dspring.profiles.active=test
• ctx.getEnvironment().setActiveProfiles(“dev”)
• <init-param> spring.profiles.active in web.xml
• @Profile(“prod”) with @Configuration

Wro4j and Profiles

@Profile

import org.springframework.context.annotation.Profile;

import java.lang.annotation.ElementType;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.annotation.Target;

@Target(ElementType.TYPE)

@Retention(RetentionPolicy.RUNTIME)

@Profile("dev")

public @interface Dev {

}

@Repository

@Dev

@Transactional(readOnly = true)

public class CustomerRepositoryImpl implements CustomerRepository {

@PersistenceContext

private EntityManager em;

Cache Abstraction

• Not an implementation, but an abstraction
• Frees you from writing logic, but does not provide stores
• JDK ConcurrentMap
• EhCache
• @Cacheable and @CacheEvict
• Can use Spring EL for “key” and “condition” attributes
• Annotations triggered by <cache:annotation-driven/>

Test Support for JavaConfig and Profiles

• Spring 3.0 added @Configuration (JavaConfig)
• TestContext Framework provides annotationdriven testing support
• Spring 3.1 adds “loader” attribute to @ContextConfiguration for @Configuration

Spring 2.0 Testing

public class CustomerRepositoryTest extends AbstractJpaTests {

private CustomerRepository customerRepository;

private EntityManagerFactory emf;

public void setCustomerRepository(CustomerRepository customerRepository) {

this.customerRepository = customerRepository;

}

public void setEntityManagerFactory(EntityManagerFactory emf) {

this.emf = emf;

}

protected String[] getConfigLocations() {

return new String[] {"repository-test-config.xml"};

}

protected void onSetUpInTransaction() throws Exception {

EntityManager em = EntityManagerFactoryUtils.getTransactionalEntityManager(emf);

Customer c = new Customer();

c.setName("Test");

c.setCustomerSince(new Date());

em.persist(c);

super.onSetUpInTransaction();

}

public void testAddCustomer() {

Customer c = new Customer();

...

TestContext with XML

@RunWith(SpringJUnit4ClassRunner.class)

@ContextConfiguration(locations = {"/repository-config.xml"})

@Transactional

@TransactionConfiguration(transactionManager = "transactionManager", defaultRollback = false)

public class CustomerRepositoryTest {

@PersistenceContext

private EntityManager em;

@Autowired

private CustomerRepository customerRepository;

@Before

@Transactional

public void onSetUpInTransaction() {

Customer c = new Customer();

c.setName("Test");

c.setCustomerSince(new Date());

em.persist(c);

}

@Test

public void testAddCustomer() {

Customer c = new Customer();

c.setName("New");

c.setCustomerSince(new Date());

customerRepository.save(c);

List<Customer> customers = customerRepository.findAll();

assertTrue(customers.contains(c));

}

TestContext with @Configuration

@RunWith(SpringJUnit4ClassRunner.class)

@ContextConfiguration(loader = AnnotationConfigContextLoader.class)

@Transactional

@TransactionConfiguration(transactionManager = "transactionManager", defaultRollback = false)

public class CustomerRepositoryTest {

@Configuration

static class ContextConfiguration {

@Bean

public CustomerRepository customerRepository() {

return new CustomerRepositoryImpl();

}

}

@PersistenceContext

private EntityManager em;

@Autowired

private CustomerRepository customerRepository;

@Before

@Transactional

public void onSetUpInTransaction() {

Customer c = new Customer();

c.setName("Test");

c.setCustomerSince(new Date());

em.persist(c);

}

@Test

public void testAddCustomer() {

Customer c = new Customer();