4. Spring 4.1增强和新功能

4. Spring 4.1增强和新功能
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4.1 JMS改进

Spring 4.1引入了一个更简单的基础架构，使用 @JmsListener注解bean方法来注册JMS监听端点。XML命名空间已经通过增强来支持这种新的方式（jms:annotation-driven），它也可以完全通过Java配置( @EnableJms, JmsListenerContainerFactory)来配置架构。也可以使用 JmsListenerConfigurer注解来注册监听端点。

Spring 4.1还调整了JMS的支持，使得你可以从spring-messaging在Spring4.0引入的抽象获益，即：

消息监听端点可以有更为灵活的签名，并且可以从标准的消息注解获益，例如@Payload、@Header、@Headers和@SendTo注解。另外，也可以使用一个标准的消息，以代替javax.jms.Message作为方法参数。
一个新的可用 JmsMessageOperations接口和允许操作使用Message抽象的JmsTemplate。

最后，Spring 4.1提供了其他各种各样的改进：

JmsTemplate中的同步请求-答复操作支持
监听器的优先权可以指定每个<jms:listener/>元素
消息侦听器容器恢复选项可以通过使用 BackOff 实现进行配置
JMS 2.0消费者支持共享

4.2 Caching（缓存）改进

Spring 4.1 支持JCache (JSR-107)注解使用Spring的现有缓存配置和基础结构的抽象；使用标准注解不需要任何更改。

Spring 4.1也大大提高了自己的缓存抽象：

缓存可以在运行时使用CacheResolver解决。因此使用value参数定义的缓存名称不在是强制性的。
更多的操作级自定义项：缓存解析器，缓存管理器，键值生成器
一个新的@CacheConfig类级别注解允许在类级别上共享常用配置，不需要启用任何缓存操作。
使用CacheErrorHandler更好的处理缓存方法的异常

Spring 4.1为了在CacheInterface添加一个新的putIfAbsent方法也做了重大的更改。

4.3 Web改进

The existing support for resource handling based on the ResourceHttpRequestHandler has been expanded with new abstractions ResourceResolver, ResourceTransformer, and ResourceUrlProvider. A number of built-in implementations provide support for versioned resource URLs (for effective HTTP caching), locating gzipped resources, generating an HTML 5 AppCache manifests, and more. See Section 16.16.7, “Serving of Resources”.
JDK 1.8’s java.util.Optional is now supported for @RequestParam, @RequestHeader, and @MatrixVariable controller method arguments.
ListenableFuture is supported as a return value alternative to DeferredResult where an underlying service (or perhaps a call to AsyncRestTemplate) already returns ListenableFuture.
@ModelAttribute methods are now invoked in an order that respects inter-dependencies. See SPR-6299.
Jackson’s @JsonView is supported directly on @ResponseBody and ResponseEntity controller methods for serializing different amounts of detail for the same POJO (e.g. summary vs. detail page). This is also supported with View-based rendering by adding the serialization view type as a model attribute under a special key. See the section called “支持 Jackson 序列化视图” for details.
JSONP is now supported with Jackson. See the section called “支持 Jackson JSONP”.
A new lifecycle option is available for intercepting @ResponseBody and ResponseEntity methods just after the controller method returns and before the response is written. To take advantage declare an @ControllerAdvice bean that implements ResponseBodyAdvice. The built-in support for @JsonView and JSONP take advantage of this. See Section 16.4.1, “使用 HandlerInterceptor 拦截请求”.
There are three new HttpMessageConverter options:
- Gson — lighter footprint than Jackson; has already been in use in Spring Android.
- Google Protocol Buffers — efficient and effective as an inter-service communication data protocol within an enterprise but can also be exposed as JSON and XML for browsers.
- Jackson based XML serialization is now supported through the jackson-dataformat-xml extension. When using @EnableWebMvc or <mvc:annotation-driven/>, this is used by default instead of JAXB2 if jackson-dataformat-xml is in the classpath.
Views such as JSPs can now build links to controllers by referring to controller mappings by name. A default name is assigned to every @RequestMapping. For example FooController with method handleFoo is named "FC#handleFoo". The naming strategy is pluggable. It is also possible to name an @RequestMapping explicitly through its name attribute. A new mvcUrl function in the Spring JSP tag library makes this easy to use in JSP pages. See Section 16.7.2, “Building URIs to Controllers and methods from views”.
ResponseEntity provides a builder-style API to guide controller methods towards the preparation of server-side responses, e.g. ResponseEntity.ok().
RequestEntity is a new type that provides a builder-style API to guide client-side REST code towards the preparation of HTTP requests.
MVC Java config and XML namespace:
- View resolvers can now be configured including support for content negotiation, see Section 16.16.6, “View Resolvers”.
- View controllers now have built-in support for redirects and for setting the response status. An application can use this to configure redirect URLs, render 404 responses with a view, send "no content" responses, etc. Some use cases are listed here.
- Path matching customizations are frequently used and now built-in. See Section 16.16.9, “Path Matching”.
Groovy markup template support (based on Groovy 2.3). See the GroovyMarkupConfigurer and respecitve ViewResolver and ‘View’ implementations.

4.4 WebSocket STOMP消息改进

SockJS (Java) client-side support. See SockJsClient and classes in same package.
New application context events SessionSubscribeEvent and SessionUnubscribeEvent published when STOMP clients subscribe and unsubscribe.
New "websocket" scope. See Section 20.4.13, “WebSocket Scope”.
@SendToUser can target only a single session and does not require an authenticated user.
@MessageMapping methods can use dot "." instead of slash "/" as path separator. See SPR-11660.
STOMP/WebSocket monitoring info collected and logged. See Section 20.4.15, “Runtime Monitoring”.
Significantly optimized and improved logging that should remain very readable and compact even at DEBUG level.
Optimized message creation including support for temporary message mutability and avoiding automatic message id and timestamp creation. See Javadoc of MessageHeaderAccessor.
STOMP/WebSocket connections that have not activity 60 seconds after the WebSocket session is established. See SPR-11884.

4.5 测试改进

Groovy scripts can now be used to configure the ApplicationContext loaded for integration tests in the TestContext framework.
- See the section called “Context configuration with Groovy scripts” for details.
Test-managed transactions can now be programmatically started and ended within transactional test methods via the new TestTransaction API.
- See the section called “Programmatic transaction management” for details.
SQL script execution can now be configured declaratively via the new @Sql and @SqlConfig annotations on a per-class or per-method basis.
- See the section called “Executing SQL scripts” for details.
Test property sources which automatically override system and application property sources can be configured via the new @TestPropertySource annotation.
- See the section called “Context configuration with test property sources” for details.
Default TestExecutionListeners can now be automatically discovered.
- See the section called “Automatic discovery of default TestExecutionListeners” for details.
Custom TestExecutionListeners can now be automatically merged with the default listeners.
- See the section called “Merging TestExecutionListeners” for details.
The documentation for transactional testing support in the TestContext framework has been improved with more thorough explanations and additional examples.
- See the section called “Transaction management” for details.
Various improvements to MockServletContext, MockHttpServletRequest, and other Servlet API mocks.
AssertThrows has been refactored to support Throwable instead of Exception.
In Spring MVC Test, JSON responses can be asserted with JSON Assert as an extra option to using JSONPath much like it has been possible to do for XML with XMLUnit.
MockMvcBuilder recipes can now be created with the help of MockMvcConfigurer. This was added to make it easy to apply Spring Security setup but can be used to encapsulate common setup for any 3rd party framework or within a project.
MockRestServiceServer now supports the AsyncRestTemplate for client-side testing.

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