This section covers what's new in Spring Framework 3.2. See also Appendix C, Migrating to Spring Framework 3.2
The Spring MVC programming model now provides explicit Servlet 3
async support. @RequestMapping
methods can
return one of:
java.util.concurrent.Callable
to
complete processing in a separate thread managed by a task executor
within Spring MVC.
org.springframework.web.context.request.async.DeferredResult
to complete processing at a later time from a thread not known to
Spring MVC — for example, in response to some external event (JMS,
AMQP, etc.)
org.springframework.web.context.request.async.AsyncTask
to wrap a Callable
and customize the
timeout value or the task executor to use.
First-class support for testing Spring MVC applications with a
fluent API and without a Servlet container. Server-side tests involve use
of the DispatcherServlet
while client-side REST
tests rely on the RestTemplate
. See Section 11.3.6, “Spring MVC Test Framework”.
A ContentNeogtiationStrategy
is now
available for resolving the requested media types from an incoming
request. The available implementations are based on the file extension,
query parameter, the 'Accept' header, or a fixed content type.
Equivalent options were previously available only in the
ContentNegotiatingViewResolver but are now available throughout.
ContentNegotiationManager
is the central
class to use when configuring content negotiation options.
For more details see Section 17.15.4, “Configuring Content Negotiation”.
The introduction of ContentNegotiationManger
also enables selective suffix pattern matching for incoming requests.
For more details, see the Javadoc of
RequestMappingHandlerMapping.setUseRegisteredSuffixPatternMatch.
Classes annotated with
@ControllerAdvice
can contain
@ExceptionHandler
,
@InitBinder
, and
@ModelAttribute
methods and those will
apply to @RequestMapping
methods across
controller hierarchies as opposed to the controller hierarchy within which
they are declared. @ControllerAdvice
is a
component annotation allowing implementation classes to be auto-detected
through classpath scanning.
A new @MatrixVariable
annotation adds
support for extracting matrix variables from the request URI. For more
details see the section called “Matrix Variables”.
An abstract base class implementation of the
WebApplicationInitializer
interface is
provided to simplify code-based registration of a DispatcherServlet and
filters mapped to it. The new class is named
AbstractDispatcherServletInitializer
and its
sub-class
AbstractAnnotationConfigDispatcherServletInitializer
can be used with Java-based Spring configuration. For more details see
Section 17.14, “Code-based Servlet container initialization”.
A convenient base class with an
@ExceptionHandler
method that handles
standard Spring MVC exceptions and returns a
ResponseEntity
that allowing customizing and
writing the response with HTTP message converters. This servers as an
alternative to the DefaultHandlerExceptionResolver
,
which does the same but returns a ModelAndView
instead.
See the revised Section 17.11, “Handling exceptions” including information on customizing the default Servlet container error page.
The RestTemplate
can now read an HTTP
response to a generic type (e.g. List<Account>
). There
are three new exchange()
methods that accept
ParameterizedTypeReference
, a new class that
enables capturing and passing generic type info.
In support of this feature, the
HttpMessageConverter
is extended by
GenericHttpMessageConverter
adding a method
for reading content given a specified parameterized type. The new
interface is implemented by the
MappingJacksonHttpMessageConverter
and also by a
new Jaxb2CollectionHttpMessageConverter
that can
read read a generic Collection
where the
generic type is a JAXB type annotated with
@XmlRootElement
or
@XmlType
.
The Jackson JSON 2 library is now supported. Due to packaging
changes in the Jackson library, there are separate classes in Spring MVC
as well. Those are
MappingJackson2HttpMessageConverter
and
MappingJackson2JsonView
. Other related
configuration improvements include support for pretty printing as well as
a JacksonObjectMapperFactoryBean
for convenient
customization of an ObjectMapper
in XML
configuration.
Tiles 3 is now supported in addition to Tiles 2.x. Configuring
it should be very similar to the Tiles 2 configuration, i.e. the
combination of TilesConfigurer
,
TilesViewResolver
and TilesView
except using the tiles3
instead of the tiles2
package.
Also note that besides the version number change, the tiles
dependencies have also changed. You will need to have a subset or all of
tiles-request-api
, tiles-api
,
tiles-core
, tiles-servlet
,
tiles-jsp
, tiles-el
.
An @RequestBody
or an
@RequestPart
argument can now be followed
by an Errors
argument making it possible to
handle validation errors (as a result of an
@Valid
annotation) locally within the
@RequestMapping
method.
@RequestBody
now also supports a required
flag.
The HTTP request method PATCH
may now be used in
@RequestMapping
methods as well as in the
RestTemplate
in conjunction with Apache
HttpComponents HttpClient version 4.2 or later. The JDK
HttpURLConnection
does not support the
PATCH
method.
Mapped interceptors now support URL patterns to be excluded. The MVC namespace and the MVC JavaConfig both expose these options.
As of 3.2, Spring allows for @Autowired
and
@Value
to be used as meta-annotations,
e.g. to build custom injection annotations in combination with specific qualifiers.
Analogously, you may build custom @Bean
definition
annotations for @Configuration
classes,
e.g. in combination with specific qualifiers, @Lazy, @Primary, etc.
Spring provides a CacheManager adapter for JCache, building against the JCache 0.5 preview release. Full JCache support is coming next year, along with Java EE 7 final.
The @DateTimeFormat
annotation can
now be used without needing a dependency on the Joda Time library. If Joda
Time is not present the JDK SimpleDateFormat
will
be used to parse and print date patterns. When Joda Time is present it
will continue to be used in preference to
SimpleDateFormat
.
It is now possible to define global formats that will be used when parsing and printing date and time types. See Section 7.7, “Configuring a global date & time format” for details.
In addition to the aforementioned inclusion of the Spring MVC Test Framework in
the spring-test
module, the Spring
TestContext Framework has been revised with support for
integration testing web applications as well as configuring application
contexts with context initializers. For further details, consult the
following.
Configuring and loading a WebApplicationContext in integration tests
Testing request and session scoped beans
Improvements to Servlet API mocks
Configuring test application contexts with ApplicationContextInitializers
Spring Framework 3.2 includes fine-tuning of concurrent data structures in many parts of the framework, minimizing locks and generally improving the arrangements for highly concurrent creation of scoped/prototype beans.
Building and contributing to the framework has never been simpler with our move to a Gradle-based build system and source control at GitHub. See the building from source section of the README and the contributor guidelines for complete details.
Last but not least, Spring Framework 3.2 comes with refined Java 7 support within the framework as well as through upgraded third-party dependencies: specifically, CGLIB 3.0, ASM 4.0 (both of which come as inlined dependencies with Spring now) and AspectJ 1.7 support (next to the existing AspectJ 1.6 support).