Version 4.2 included a number of improvements, as described in the following sections:
@Bean get detected and processed on Java 8 default methods as well,
allowing for composing a configuration class from interfaces with default @Bean methods.
@Import with regular component classes now, allowing
for a mix of imported configuration classes and component classes.
@Order value, getting processed in a corresponding
order (e.g. for overriding beans by name) even when detected through classpath scanning.
@Resource injection points support an @Lazy declaration, analogous to @Autowired,
receiving a lazy-initializing proxy for the requested target bean.
The application event infrastructure now offers an annotation-based model as well as the ability to publish any arbitrary event.
@EventListener to consume events.
@TransactionalEventListener provides transaction-bound event support.
Spring Framework 4.2 introduces first-class support for declaring and
looking up aliases for annotation attributes. The new @AliasFor
annotation can be used to declare a pair of aliased attributes within
a single annotation or to declare an alias from one attribute in a
custom composed annotation to an attribute in a meta-annotation.
@AliasFor support
in order to provide meaningful aliases for their value attributes:
@Cacheable, @CacheEvict, @CachePut, @ComponentScan,
@ComponentScan.Filter, @ImportResource, @Scope, @ManagedResource,
@Header, @Payload, @SendToUser, @ActiveProfiles,
@ContextConfiguration, @Sql, @TestExecutionListeners,
@TestPropertySource, @Transactional, @ControllerAdvice,
@CookieValue, @CrossOrigin, @MatrixVariable, @RequestHeader,
@RequestMapping, @RequestParam, @RequestPart, @ResponseStatus,
@SessionAttributes, @ActionMapping, @RenderMapping,
@EventListener, @TransactionalEventListener.
For example, @ContextConfiguration from the spring-test module
is now declared as follows:
public @interface ContextConfiguration { @AliasFor("locations") String[] value() default {}; @AliasFor("value") String[] locations() default {}; // ... }
@AliasFor for fine-grained control
over exactly which attributes are overridden within an annotation
hierarchy. In fact, it is now possible to declare an alias for the
value attribute of a meta-annotation.
For example, one can now develop a composed annotation with a custom attribute override as follows.
@ContextConfiguration public @interface MyTestConfig { @AliasFor(annotation = ContextConfiguration.class, attribute = "value") String[] xmlFiles(); // ... }
AnnotationAttributes instances)
can be synthesized (i.e., converted) into an annotation.
DirectFieldAccessor) have been aligned with the current
property-based data binding (BeanWrapper). In particular, field-based binding now supports
navigation for Collections, Arrays, and Maps.
DefaultConversionService now provides out-of-the-box converters for Stream, Charset,
Currency, and TimeZone. Such converters can be added individually to any arbitrary
ConversionService as well.
DefaultFormattingConversionService comes with out-of-the-box support for the value types
in JSR-354 Money & Currency (if the 'javax.money' API is present on the classpath): namely,
MonetaryAmount and CurrencyUnit. This includes support for applying @NumberFormat.
@NumberFormat can now be used as a meta-annotation.
JavaMailSenderImpl has a new testConnection() method for checking connectivity to the server.
ScheduledTaskRegistrar exposes scheduled tasks.
commons-pool2 is now supported for a pooling AOP CommonsPool2TargetSource.
StandardScriptFactory as a JSR-223 based mechanism for scripted beans,
exposed through the lang:std element in XML. Supports e.g. JavaScript and JRuby.
(Note: JRubyScriptFactory and lang:jruby are deprecated now, in favor of using JSR-223.)
javax.transaction.Transactional is now supported via AspectJ.
SimpleJdbcCallOperations now supports named binding.
org.springframework.orm.hibernate5 package).
<jdbc:embedded-database> supports a new database-name attribute.
See "Testing Improvements" below for further details.
autoStartup attribute can be controlled via JmsListenerContainerFactory.
Destination can now be configured per listener container.
@SendTo annotation can now use a SpEL expression.
JmsResponse
@JmsListener is now a repeatable annotation to declare several JMS containers on the same
method (use the newly introduced @JmsListeners if you’re not using Java8 yet).
@CrossOrigin) configuration. See Chapter 27, CORS Support for details.
HTTP caching updates:
CacheControl builder; plugged into ResponseEntity, WebContentGenerator,
ResourceHttpRequestHandler.
WebRequest.
@RequestMapping as a meta-annotation.
AbstractHandlerMethodMapping to register and unregister request
mappings at runtime.
createDispatcherServlet method in AbstractDispatcherServletInitializer to
further customize the DispatcherServlet instance to use.
HandlerMethod as a method argument on @ExceptionHandler methods, especially
handy in @ControllerAdvice components.
java.util.concurrent.CompletableFuture as an @Controller method return value type.
HttpHeaders and for serving static resources.
@ResponseStatus detected on nested exceptions.
UriTemplateHandler extension point in the RestTemplate.
DefaultUriTemplateHandler exposes baseUrl property and path segment encoding options.
RestTemplate.
baseUrl alternative for methods in MvcUriComponentsBuilder.
RequestBodyAdvice extension point and built-in implementation to support Jackson’s
@JsonView on @RequestBody method arguments.
List<Foo>.
ScriptTemplateView as a JSR-223 based mechanism for scripted web views,
with a focus on JavaScript view templating on Nashorn (JDK 8).
Expose presence information about connected users and subscriptions:
SimpUserRegistry exposed as a bean named "userRegistry".
StompSubProtocolErrorHandler extension point to customize and control STOMP ERROR frames to clients.
@MessageExceptionHandler methods via @ControllerAdvice components.
SimpleBrokerMessageHandler.
@SendTo and @SendToUser can contain destination variable placeholders.
@JsonView supported for return values on @MessageMapping and @SubscribeMapping methods.
ListenableFuture and CompletableFuture as return value types from
@MessageMapping and @SubscribeMapping methods.
MarshallingMessageConverter for XML payloads.
JUnit-based integration tests can now be executed with JUnit rules instead of the
SpringJUnit4ClassRunner. This allows Spring-based integration tests to be run with
alternative runners like JUnit’s Parameterized or third-party runners such as the
MockitoJUnitRunner.
The Spring MVC Test framework now provides first-class support for HtmlUnit, including integration with Selenium’s WebDriver, allowing for page-based web application testing without the need to deploy to a Servlet container.
AopTestUtils is a new testing utility that allows developers to
obtain a reference to the underlying target object hidden behind one
or more Spring proxies.
ReflectionTestUtils now supports setting and getting static fields,
including constants.
@ActiveProfiles is now retained in order to support use cases such
as Spring Boot’s ConfigFileApplicationListener which loads
configuration files based on the names of active profiles.
@DirtiesContext supports new BEFORE_METHOD, BEFORE_CLASS, and
BEFORE_EACH_TEST_METHOD modes for closing the ApplicationContext
before a test — for example, if some rogue (i.e., yet to be
determined) test within a large test suite has corrupted the original
configuration for the ApplicationContext.
@Commit is a new annotation that may be used as a direct replacement for
@Rollback(false).
@Rollback may now be used to configure class-level default rollback semantics.
@TransactionConfiguration is now deprecated and will be removed in a
subsequent release.
@Sql now supports execution of inlined SQL statements via a new
statements attribute.
ContextCache that is used for caching ApplicationContexts
between tests is now a public API with a default implementation that
can be replaced for custom caching needs.
DefaultTestContext, DefaultBootstrapContext, and
DefaultCacheAwareContextLoaderDelegate are now public classes in the
support subpackage, allowing for custom extensions.
TestContextBootstrappers are now responsible for building the
TestContext.
MvcResult details can now be logged
at DEBUG level or written to a custom OutputStream or Writer. See
the new log(), print(OutputStream), and print(Writer) methods in
MockMvcResultHandlers for details.
database-name attribute in
<jdbc:embedded-database>, allowing developers to set unique names
for embedded databases –- for example, via a SpEL expression or a
property placeholder that is influenced by the current active bean
definition profiles.
Embedded databases can now be automatically assigned a unique name,
allowing common test database configuration to be reused in different
ApplicationContexts within a test suite.
MockHttpServletRequest and MockHttpServletResponse now provide better
support for date header formatting via the getDateHeader and setDateHeader
methods.