spring mvc <mvc:annotation-driver/>详解

- 日理万妓 2022-08-23 08:42 165阅读 0赞

To enable MVC Java config add the annotation `@EnableWebMvc` to one of your `@Configuration` classes:

@Configuration
    @EnableWebMvc
    public class WebConfig {
    
    }

To achieve the same in XML use the `mvc:annotation-driven` element in your DispatcherServlet context (or in your root context if you have no DispatcherServlet context defined):

<?xml version="1.0" encoding="UTF-8"?>
    <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:

1.  Spring 3 style type conversion through a [ConversionService][] instance in addition to the JavaBeans PropertyEditors used for Data Binding.
2.  Support for [formatting][] Number fields using the `@NumberFormat` annotation through the `ConversionService`.
3.  Support for [formatting][] `Date`, `Calendar`, `Long`, and Joda Time fields using the `@DateTimeFormat` annotation.
4.  Support for [validating][] `@Controller` inputs with `@Valid`, if a JSR-303 Provider is present on the classpath.
5.  `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:
    
    1.  `ByteArrayHttpMessageConverter` converts byte arrays.
    2.  `StringHttpMessageConverter` converts strings.
    3.  `ResourceHttpMessageConverter` converts to/from `org.springframework.core.io.Resource` for all media types.
    4.  `SourceHttpMessageConverter` converts to/from a `javax.xml.transform.Source`.
    5.  `FormHttpMessageConverter` converts form data to/from a `MultiValueMap<String, String>`.
    6.  `Jaxb2RootElementHttpMessageConverter` converts Java objects to/from XML — added if JAXB2 is present and Jackson 2 XML extension is not present on the classpath.
    7.  `MappingJackson2HttpMessageConverter` converts to/from JSON — added if Jackson 2 is present on the classpath.
    8.  `MappingJackson2XmlHttpMessageConverter` converts to/from XML — added if [Jackson 2 XML extension][] is present on the classpath.
    9.  `AtomFeedHttpMessageConverter` converts Atom feeds — added if Rome is present on the classpath.
    10. `RssChannelHttpMessageConverter` converts RSS feeds — added if Rome is present on the classpath.

See [Section 22.16.12, “Message Converters”][Section_22.16.12_ _Message Converters] for more information about how to customize these default converters.

<table style="border-spacing:0px; line-height:1.6; margin:0px; border:none!important; background:none!important"> 
 <tbody style="margin:0px; border:none!important; background:none!important"> 
  <tr style="border:none!important; margin:0px; background:none!important"> 
   <td align="center" style="padding:10px 13px 6px; border-right-width:1px!important; border-style:none solid none none!important; border-right-color:rgb(204,204,204)!important; margin:0px; background:none!important"> <img alt="[Note]" src="http://docs.spring.io/spring/docs/current/spring-framework-reference/html/images/note.png" style="margin:0px; border:none!important; background:none!important"></td> 
  </tr> 
  <tr style="border:none!important; margin:0px; background-color:rgb(248,248,248)"> 
   <td align="left" style="padding:6px 13px; border:none!important; margin:0px; background:none!important"> <p style="margin-top:0px; margin-bottom:0px; color:rgb(111,111,111); line-height:1.6; border:none!important; background:none!important"> Jackson JSON and XML converters are created using&nbsp;<code style="font-size:16px; font-family:Consolas,&quot;Liberation Mono&quot;,Courier,monospace; color:rgb(109,24,11); border:1px solid rgb(204,204,204)!important; padding:1px 3px 0px!important; white-space:nowrap!important; margin:0px; background:none rgb(242,242,242)!important">ObjectMapper</code>&nbsp;instances created by&nbsp;<a href="http://docs.spring.io/spring-framework/docs/4.3.0.RELEASE/javadoc-api/org/springframework/http/converter/json/Jackson2ObjectMapperBuilder.html" style="color:rgb(65,131,196); text-decoration:none; margin:0px; border:none!important; background:none!important" rel="nofollow"><code style="font-size:16px; font-family:Consolas,&quot;Liberation Mono&quot;,Courier,monospace; color:rgb(109,24,11); border:1px solid rgb(204,204,204)!important; padding:1px 3px 0px!important; white-space:nowrap!important; margin:0px; background:none rgb(242,242,242)!important">Jackson2ObjectMapperBuilder</code></a>&nbsp;in order to provide a better default configuration.</p> <p style="margin-top:0px; margin-bottom:0px; color:rgb(111,111,111); line-height:1.6; border:none!important; background:none!important"> This builder customizes Jackson’s default properties with the following ones:</p> 
    <div style="margin:0px; border:none!important; background:none!important"> 
     <ol style="padding-left:30px; margin:0px; border:none!important; background:none!important"> 
      <li style="margin:0px; border:none!important; background:none!important"> <a href="http://fasterxml.github.io/jackson-databind/javadoc/2.6/com/fasterxml/jackson/databind/DeserializationFeature.html#FAIL_ON_UNKNOWN_PROPERTIES" style="color:rgb(65,131,196); text-decoration:none; margin:0px; border:none!important; background:none!important" rel="nofollow"><code style="font-size:16px; font-family:Consolas,&quot;Liberation Mono&quot;,Courier,monospace; color:rgb(109,24,11); border:1px solid rgb(204,204,204)!important; padding:1px 3px 0px!important; white-space:nowrap!important; margin:0px; background:none rgb(242,242,242)!important">DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES</code></a>&nbsp;is disabled.</li> 
      <li style="margin:0px; border:none!important; background:none!important"> <a href="http://fasterxml.github.io/jackson-databind/javadoc/2.6/com/fasterxml/jackson/databind/MapperFeature.html#DEFAULT_VIEW_INCLUSION" style="color:rgb(65,131,196); text-decoration:none; margin:0px; border:none!important; background:none!important" rel="nofollow"><code style="font-size:16px; font-family:Consolas,&quot;Liberation Mono&quot;,Courier,monospace; color:rgb(109,24,11); border:1px solid rgb(204,204,204)!important; padding:1px 3px 0px!important; white-space:nowrap!important; margin:0px; background:none rgb(242,242,242)!important">MapperFeature.DEFAULT_VIEW_INCLUSION</code></a>&nbsp;is disabled.</li> 
     </ol> 
    </div> <p style="margin-top:0px; margin-bottom:0px; color:rgb(111,111,111); line-height:1.6; border:none!important; background:none!important"> It also automatically registers the following well-known modules if they are detected on the classpath:</p> 
    <div style="margin:0px; border:none!important; background:none!important"> 
     <ol style="padding-left:30px; margin:0px; border:none!important; background:none!important"> 
      <li style="margin:0px; border:none!important; background:none!important"> <a href="https://github.com/FasterXML/jackson-datatype-jdk7" style="color:rgb(65,131,196); text-decoration:none; margin:0px; border:none!important; background:none!important" rel="nofollow">jackson-datatype-jdk7</a>: support for Java 7 types like&nbsp;<code style="font-size:16px; font-family:Consolas,&quot;Liberation Mono&quot;,Courier,monospace; color:rgb(109,24,11); border:1px solid rgb(204,204,204)!important; padding:1px 3px 0px!important; white-space:nowrap!important; margin:0px; background:none rgb(242,242,242)!important">java.nio.file.Path</code>.</li> 
      <li style="margin:0px; border:none!important; background:none!important"> <a href="https://github.com/FasterXML/jackson-datatype-joda" style="color:rgb(65,131,196); text-decoration:none; margin:0px; border:none!important; background:none!important" rel="nofollow">jackson-datatype-joda</a>: support for Joda-Time types.</li> 
      <li style="margin:0px; border:none!important; background:none!important"> <a href="https://github.com/FasterXML/jackson-datatype-jsr310" style="color:rgb(65,131,196); text-decoration:none; margin:0px; border:none!important; background:none!important" rel="nofollow">jackson-datatype-jsr310</a>: support for Java 8 Date &amp; Time API types.</li> 
      <li style="margin:0px; border:none!important; background:none!important"> <a href="https://github.com/FasterXML/jackson-datatype-jdk8" style="color:rgb(65,131,196); text-decoration:none; margin:0px; border:none!important; background:none!important" rel="nofollow">jackson-datatype-jdk8</a>: support for other Java 8 types like&nbsp;<code style="font-size:16px; font-family:Consolas,&quot;Liberation Mono&quot;,Courier,monospace; color:rgb(109,24,11); border:1px solid rgb(204,204,204)!important; padding:1px 3px 0px!important; white-space:nowrap!important; margin:0px; background:none rgb(242,242,242)!important">Optional</code>.</li> 
     </ol> 
    </div> </td> 
  </tr> 
 </tbody> 
</table>

[ConversionService]: http://docs.spring.io/spring/docs/current/spring-framework-reference/html/validation.html#core-convert
[formatting]: http://docs.spring.io/spring/docs/current/spring-framework-reference/html/validation.html#format
[validating]: http://docs.spring.io/spring/docs/current/spring-framework-reference/html/mvc.html#mvc-config-validation
[Jackson 2 XML extension]: https://github.com/FasterXML/jackson-dataformat-xml
[Section_22.16.12_ _Message Converters]: http://docs.spring.io/spring/docs/current/spring-framework-reference/html/mvc.html#mvc-config-message-converters