Spring Framework 4.1

Sam Brannen @sam_brannen

Sam Brannen •  Spring and Java Consultant @ Swiftmind •  Java Developer for over 15 years

•  Spring Framework Core Committer since 2007 •  Component lead for spring-test

•  Spring Trainer •  Speaker on Spring, Java, and testing

•  Swiss Spring User Group Lead

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Areas of expertise –  Spring * –  Java EE –  Software Architecture –  Software Engineering Best

Practices

Where you find us •  Zurich, Switzerland •  @swiftmind •  http://www.swiftmind.com

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Your experts for Spring & Enterprise Java

A show of hands…

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Agenda •  Container enhancements •  Caching •  JMS •  Spring MVC •  Testing •  Q&A

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Container Enhancements

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Enhancements in 4.1 •  java.util.Optional

•  Dependency injection •  MVC method arguments

•  @Order on @Bean methods •  Injecting ordered lists

•  @Priority (javax.annotation) •  Ordering •  Primary candidate selection

•  SpEL compiler •  Modes: off, immediate, mixed •  System / Spring property: spring.expression.compiler.mode

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Injection point with required flag @Servicepublic class MyService {

@Autowired(required=false) NotificationService notificationService;

public Book findBook(long id) { if (notificationService != null) { /* ... */ } }}

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before

Injection point with java.util.Optional @Servicepublic class MyService {

@Autowired Optional<NotificationService> notificationService;

public Book findBook(long id) { notificationService.ifPresent(service -> /* ... */ ); }}

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after

@Order on Components (4.0) @Service @Order(1)public class ServiceA implements MyService { /* ... */ }

@Service @Order(2)public class ServiceB implements MyService { /* ... */ }

@AutowiredList<MyService> myServices;

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ServiceA is 1st

@Order on @Bean Methods (4.1) @Bean @Order(1)public MyService serviceA() { return new ServiceA(); }

@Bean @Order(2)public MyService serviceB() { return new ServiceB(); }

@AutowiredList<MyService> myServices;

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ServiceA is 1st

Caching

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New Caching Features •  @CacheConfig

•  common class-level configuration

•  CacheResolver •  fine grained, programmatic cache resolution

•  JCache (JSR-107)

•  New putIfAbsent() method in Cache API

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Review: Spring Caching API

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“books” cache name is duplicated everywhere. L

@CacheConfig

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“books” cache name is declared only once! J

CacheResolver API

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•  getOperation() •  getTarget() •  getMethod() •  getArgs()

JCache (JSR 107) and Spring •  JCache 1.0 annotations now supported in Spring

•  Integration based on Spring’s own Cache and CacheManager APIs •  JCacheCache and JCacheCacheManager

•  Enabled via Spring’s standard mechanisms: •  XML: <cache:annotation-driven />•  Java: @EnableCaching

•  Cache Abstraction: JCache (JSR-107) Annotations Support •  https://spring.io/blog/2014/04/14/cache-abstraction-jcache-jsr-107-annotations-support

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JCache Annotations Support

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Caching Annotations Comparison

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Spring JCache @Cacheable @CacheResult@CachePut @CachePut@CacheEvict @CacheRemove@CacheEvict(allEntries=true) @CacheRemoveAll

JMS

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JMS Overhaul •  Alignment with spring-messaging module

•  Annotation-driven endpoints •  Analogous to <jms:listener-container /> •  Listener methods declared via @JmsListener•  Configured via:

o  XML: <jms:annotation-driven />o  Java: @EnableJms and JmsListenerConfigurer

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Review: Spring JMS Config in XML

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Annotated JMS Endpoints

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Flexible Method Signatures

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Transition from existing XML config…

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… or remove XML altogether

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Spring MVC

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ResponseBodyAdvice •  Callback for @ResponseBody / ResponseEntity methods

•  just before the response is written (and committed) •  you can still modify headers •  or the object to be written to the response

•  Two implementations already •  JsonViewResponseBodyAdvice •  AbstractJsonpResponseBodyAdvice

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Jackson @JsonView Support interface PublicView {}

class User {

@JsonView(PublicView.class) String username;

String password;

// ...}

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@RestControllerclass UserController {

@RequestMapping("/user") @JsonView(PublicView.class) public User getUser() { return new User("eric", "7!#H2"); }}

JSONP Support •  Simply declare as a Spring-managed component…

@ControllerAdviceclass JsonpAdvice extends AbstractJsonpResponseBodyAdvice {

public JsonpAdvice() { super("callback"); }}

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Name of JSONP query param(s)

HttpMessageConverter Additions •  Gson

•  lighter footprint (vs Jackson); used in Spring Android

•  Google Protocol Buffers •  effective inter-service communication data protocol

•  Jackson / XML •  just add jackson-dataformat-xml to the classpath

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Static Resource Handling in Web MVC •  ResourceTransformer API

•  Transforms the content of a resource

•  ResourceResolver API for resolving: •  Internal static resources •  External resource paths (i.e., links)

•  ResourceResolverChain •  Maintains a chain of resolvers •  Allowing for delegation

•  Configured via ResourceHandlerRegistry•  For example, via WebMvcConfigurationSupport

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ResourceResolver Implementations •  PathResourceResolver

•  simple path lookup under configured locations

•  VersionResourceResolver •  resolution with version in URL path

•  GzipResourceResolver •  lookup with .gz extension when “Accept-Encoding: gzip”

•  CachingResourceResolver •  caching of resolved resource

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ResourceTransformer Implementations •  CssLinkResourceTransformer

•  update links in CSS file (e.g. insert version)

•  AppCacheManifestTransformer •  update links in HTML5 AppCache manifest •  insert comment with content-based hash

•  CachingResourceTransformer •  caching of transformed resource

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Ex: Fingerprinting URLs w/ content-based version boolean useResourceCache = !this.environment.acceptsProfiles("dev");

VersionResourceResolver resolver = new VersionResourceResolver();resolver.addContentVersionStrategy("/**");

registry.addResourceHandler("/**").addResourceLocations(locations) .resourceChain(useResourceCache).addResolver(resolver);

Example URL: “/css/font-awesome.min-7fbe76cdac.css”

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Additional New Features in Spring MVC •  Groovy markup templates •  Declarative MVC view resolution •  Enhanced view controllers •  Linking to @RequestMapping methods

•  See HandlerMethodMappingNamingStrategy

•  ListenableFuture return type for handler methods •  ResponseEntity Builder API •  RequestEntity & RestTemplate.exchange()

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Testing

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Bootstrap Strategy & TestExecutionListeners •  TestContext bootstrap strategy

•  TestContextBootstrapper & @BootstrapWith

•  Automatic discovery of default TestExecutionListeners •  Uses SpringFactoriesLoader •  Already used by Spring Security

•  Merging custom TestExecutionListeners with defaults •  @TestExecutionListeners(mergeMode=MERGE_WITH_DEFAULTS) •  Defaults to REPLACE_DEFAULTS

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Spring MVC Test •  Assert JSON responses with JSON Assert

•  Complements JSONPath support

•  Create MockMvcBuilder recipes with MockMvcConfigurer •  Developed to apply Spring Security setup but can be used by anyone

•  AsyncRestTemplate support in MockRestServiceServer •  For asynchronous client-side testing

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Groovy Beans in Spring •  Spring Framework 4.0 introduced support for the Groovy Bean

Definition DSL via the GroovyBeanDefinitionReader and GenericGroovyApplicationContext

•  Spring Framework 4.1 introduces support for Groovy scripts in web applications via the GroovyWebApplicationContext

•  Testing support added in 4.1…

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Groovy Scripts for Context Config in Tests •  Spring Framework 4.1 introduces support for Groovy scripts in

integration tests via @ContextConfiguration •  Scripts are configured via the locations or value attribute

o  Resource semantics identical to XML o  Default detected with “Context.groovy” suffix in same package

•  The inheritLocations flag is fully supported

•  Groovy and XML configuration can be declared together

•  Groovy WebApplicationContexts supported via @WebAppConfiguration

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Ex: Groovy Script Config @RunWith(SpringJUnit4ClassRunner.class)@ContextConfiguration("/context.groovy")public class GroovyPersonTests {

@Autowired private Person person;

/* test methods using person bean */}

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Ex: Default Groovy Script Detection public com.example;

@RunWith(SpringJUnit4ClassRunner.class)// ApplicationContext will be loaded from// “classpath:com/example/MyTestContext.groovy”@ContextConfigurationpublic class MyTest { /* ... */}

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Ex: Groovy & XML Config Together @RunWith(SpringJUnit4ClassRunner.class)// ApplicationContext will be loaded from// “/context.groovy” and “/context.xml”@ContextConfiguration({ "/context.groovy", "/context.xml" })public class MyTest { /* ... */}

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Test Property Sources •  Spring 3.1 introduced PropertySources abstraction

•  Configured via Environment or via @PropertySource

•  Spring 4.1 supports declarative test property sources •  Configured via @TestPropertySource

•  Test property sources are declared via annotation attributes •  locations or value: resource locations •  properties: inlined properties •  both are inherited by default

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@TestPropertySource – locations •  String array of resource locations for Java Properties files

•  Both traditional *.properties and XML formats are supported

•  Resource semantics are identical to those for locations in @ContextConfiguration

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Ex: @TestPropertySource – locations @ContextConfiguration@TestPropertySource("/test.properties")public class MyIntegrationTests {

// class body...}

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@TestPropertySource – properties •  Inlined properties can be declared as key/value pairs

•  Uses syntax for entries in Java properties files: •  "key=value" •  "key:value" •  "key value"

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Ex: @TestPropertySource – properties @ContextConfiguration@TestPropertySource( properties = {"foo=bar", "port: 4242"})public class MyIntegrationTests {

// class body...}

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Default Properties File Detection •  If neither locations nor properties are defined, a default properties

file will be detected

•  Default is detected with “.properties” suffix in same package

•  If the class is com.example.MyTest, the default properties file is “classpath:com/example/MyTest.properties”

•  Exception is thrown if default is not present

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@TestPropertySource – Precedence

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Inlined

Files

Application & System

test

prec

eden

ce

Ex: @TestPropertySource – locations & properties @ContextConfiguration@TestPropertySource( locations = "/test.properties", properties = "port: 4242")public class MyIntegrationTests {

// class body...}

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Programmatic Transaction Management in Tests •  History Lesson: Spring’s JUnit 3.8 testing framework supported

endTransaction() and startNewTransaction() methods in AbstractTransactionalSpringContextTests

•  But… the Spring TestContext Framework, introduced in Spring 2.5, did not… until now

•  Due to popular demand, Spring 4.1 introduces a new TestTransaction API

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Transactions in Spring •  Spring-managed transactions: managed by Spring in the

ApplicationContext •  @Transactional and AOP

•  Application-managed transactions: managed programmatically within application code

•  TransactionTemplate and TransactionSynchronizationManager

•  Test-managed transactions: managed by the Spring TestContext Framework

•  @Transactional on test classes and test methods •  Transaction is rolled back by default!

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Ex: Declarative Transaction Management in Tests @RunWith(SpringJUnit4ClassRunner.class)@ContextConfiguration@Transactionalpublic class TransactionalTests {

@Test public void withinTransaction() { /* ... */ }

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What if we want to stop & start the

transaction within the test method?

TestTransaction API •  Static methods for interacting with test-managed transactions

•  isActive() •  isFlaggedForRollback()

•  flagForCommit() •  flagForRollback()

•  end() •  start()

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query status

change default rollback setting

end: roll back or commit based on flag start: new tx with default rollback setting

Ex: Programmatic Tx Management in Tests @Testpublic void withinTransaction() { // assert initial state in test database: assertNumUsers(2);

deleteFromTables("user");

// changes to the database will be committed TestTransaction.flagForCommit(); TestTransaction.end(); assertFalse(TestTransaction.isActive()); assertNumUsers(0);

TestTransaction.start(); // perform other actions against the database that will // be automatically rolled back after the test completes...}

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Executing SQL Scripts

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Ex: Embedded Database in Java Config

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@Beanpublic DataSource dataSource() { return new EmbeddedDatabaseBuilder() .setType(H2) .setScriptEncoding("UTF-8") .ignoreFailedDrops(true) .addScript("schema.sql") .addScripts("user_data.sql", "country_data.sql") .build();}

API greatly improved in Spring 4.0.3

Ex: Embedded Database in XML Config <jdbc:embedded-database id="dataSource" type="H2"> <jdbc:script location="classpath:/schema.sql" /> <jdbc:script location="classpath:/user_data.sql" /></jdbc:embedded-database>

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Ex: Populate Database in XML Config <jdbc:initialize-database data-source="dataSource"> <jdbc:script location="classpath:/schema_01.sql" /> <jdbc:script location="classpath:/schema_02.sql" /> <jdbc:script location="classpath:/data_01.sql" /> <jdbc:script location="classpath:/data_02.sql" /></jdbc:initialize-database>

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Executing SQL per Test Method •  The previous techniques are very useful for setting up the initial

database state

•  Q: But how can we execute SQL scripts per test method? •  A: Programmatically via ScriptUtils,

ResourceDatabasePopulator, or abstract transactional base test classes for JUnit and TestNG.

•  Q: OK, but how can we do that declaratively? •  A: Via @Sql in Spring Framework 4.1!

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Executing SQL Scripts Declaratively with @Sql •  @Sql: declared on a test class or test method

•  method-level overrides class-level

•  The scripts attribute is used to declare resource locations for SQL scripts

•  semantics analogous to locations in @ContextConfiguration

•  Scripts can be executed before or after a test method •  configured via the executionPhase attribute of @Sql

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Ex: @Sql in Action @ContextConfiguration@Sql({ "schema1.sql", "data1.sql" })public class SqlScriptsTests {

@Test public void classLevelScripts() { /* ... */ }

@Test @Sql({ "schema2.sql", "data2.sql" }) public void methodLevelScripts() { /* ... */ }

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Default SQL Script Detection •  If no scripts are declared, a default script will be detected

•  Depending on where @Sql is declared

•  Class-level: for com.example.DbTest, the default is “classpath:com/example/DbTest.sql”

•  Method-level: for com.example.DbTest.test(), the default is “classpath:com/example/DbTest.test.sql”

•  If the default is not present, an exception is thrown

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Declaring Multiple @Sql Sets •  Declare multiple sets of @Sql scripts for varying configuration

•  Java 8: use @Sql as a repeatable annotation

•  Java 6 & 7: wrap @Sql sets in @SqlGroup

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@Sql as a Repeatable Annotation (Java 8)

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@Test@Sql( scripts="/test-schema.sql", config = @SqlConfig(commentPrefix = "`")@Sql("/user-data.sql")public void userTest() { // code that uses the test schema and test data}

Schema uses custom syntax

@Sql wrapped in @SqlGroup (Java 6 & 7)

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@Test@SqlGroup({ @Sql( scripts="/test-schema.sql", config = @SqlConfig(commentPrefix = "`"), @Sql("/user-data.sql")})public void userTest() { // code that uses the test schema and test data}

Configuring SQL Scripts with @SqlConfig •  @SqlConfig: configures script parsing and error handling

•  Class-level: serves as global configuration for the test class •  @Sql(config): serves as local configuration for the enclosing @Sql

•  Local configuration inherits global configuration and can selectively override global configuration

•  Transaction management for script execution is configured via the dataSource, transactionManager, and transactionMode attributes

•  See Javadoc and reference manual for details

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In closing…

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Spring Resources

Spring Framework: http://projects.spring.io/spring-framework Spring Guides: http://spring.io/guides Spring JIRA: https://jira.spring.io

Spring on GitHub: https://github.com/spring-projects/spring-framework Stack Overflow: spring, spring-test, spring-mvc, …

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Blogs Spring Blog: http://spring.io/blog Swiftmind Blog: http://www.swiftmind.com/blog

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Q & A Sam Brannen

@sam_brannen

www.slideshare.net/sbrannen

www.swiftmind.com

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@springcentral spring.io/video