Spring MVC 中， 标签的注意点

是一种简写形式，完全可以手动配置替代这种简写形式，简写形式可以让初学都快速应用默认配置方案。

会自动注册 DefaultAnnotationHandlerMapping 与 AnnotationMethodHandlerAdapter 这两个bean, 它们是 Spring MVC 为 @Controller 分发请求所必须的。

这段话我在很多帖子都看到过，我自己的项目本身使用的Spring MVC 4.3.5，实际上在3.1之后，注册的类是发生了变化的。

下面是官方文档里的说明：

Spring Framework 3.1 introduces a new set of support classes for processing requests with annotated controllers:

• RequestMappingHandlerMapping
• RequestMappingHandlerAdapter
• ExceptionHandlerExceptionResolver

These classes are a replacement for the existing:

• DefaultAnnotationHandlerMapping
• AnnotationMethodHandlerAdapter
• AnnotationMethodHandlerExceptionResolver

<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">

    <mvc:annotation-driven />

beans>

The above registers a RequestMappingHandlerMapping, a RequestMappingHandlerAdapter, and an ExceptionHandlerExceptionResolver (among others) in support of processing requests with annotated controller methods using annotations such as @RequestMapping , @ExceptionHandler, and others.

It also enables the following:

• Spring 3 style type conversion through a ConversionService instance in addition to the JavaBeans PropertyEditors used for Data Binding.
• Support for formatting Number fields using the @NumberFormat annotation through the ConversionService.
• Support for formatting Date, Calendar, Long, and Joda Time fields using the @DateTimeFormat annotation.
• Support for validating @Controller inputs with @Valid, if a JSR-303 Provider is present on the classpath.
• HttpMessageConverter support for @RequestBody method parameters and @ResponseBody method return values from @RequestMapping or @ExceptionHandler methods.

  This is the complete list of HttpMessageConverters set up by mvc:annotation-driven:

• ByteArrayHttpMessageConverter converts byte arrays.
• StringHttpMessageConverter converts strings.
• ResourceHttpMessageConverter converts to/from org.springframework.core.io.Resource for all media types.
• SourceHttpMessageConverter converts to/from a javax.xml.transform.Source.
• FormHttpMessageConverter converts form data to/from a MultiValueMap.
• Jaxb2RootElementHttpMessageConverter converts Java objects to/from XML — added if JAXB2 is present on the classpath.
• MappingJackson2HttpMessageConverter (or MappingJacksonHttpMessageConverter) converts to/from JSON — added if Jackson 2 (or Jackson) is present on the classpath.
• AtomFeedHttpMessageConverter converts Atom feeds — added if Rome is present on the classpath.
• RssChannelHttpMessageConverter converts RSS feeds — added if Rome is present on the classpath.

这是摘取的官方文档，可以看出，注册的类已经变成了RequestMappingHandlerMapping和 RequestMappingHandlerAdapter。

转自：mvc:annotation-driven 的变更