Spring MVC之messageConverters

时间：2023-03-09 23:56:09
Spring MVC之messageConverters

<mvc:annotation-driven /> 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。<mvc:annotation-driven /> 会自动注册DefaultAnnotationHandlerMapping与AnnotationMethodHandlerAdapter 两个bean,是spring MVC为@Controllers分发请求所必须的。

这句话我在很多帖子都看到过，我自己的项目本身使用的Spring MVC 3.2，实际上在3.1之后，<mvc:annotation-driven />注册的类发生了变化

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

  1. <?xml version="1.0" encoding="UTF-8"?>
  2. <beans xmlns="http://www.springframework.org/schema/beans"
  3. xmlns:mvc="http://www.springframework.org/schema/mvc"
  4. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  5. xsi:schemaLocation="
  6. http://www.springframework.org/schema/beans
  7. http://www.springframework.org/schema/beans/spring-beans.xsd
  8. http://www.springframework.org/schema/mvc
  9. http://www.springframework.org/schema/mvc/spring-mvc.xsd">
  10. <mvc:annotation-driven />
  11. </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:

    • 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<String, String>.

    • 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。

我之前在不知道的时候，使用AnnotationMethodHandlerAdapter 进行配置，结果在有<mvc:annotation-driven />存在的情况下，我自己配置的AnnotationMethodHandlerAdapter 怎么都不起作用，于是去掉了<mvc:annotation-driven />标签，手动注册了AnnotationMethodHandlerAdapter ，和DefaultAnnotationHandlerMapping。结果引发了其他问题，比如文件无法上传的问题。

阅读文档发现Spring提供了基于<mvc:annotation-driven />自定义messageConverters的方法，如下所示：

  1. <mvc:annotation-driven conversion-service="conversionService">
  2. <mvc:message-converters>
  3. <bean class="org.example.MyHttpMessageConverter"/>
  4. <bean class="org.example.MyOtherHttpMessageConverter"/>
  5. </mvc:message-converters>
  6. </mvc:annotation-driven>

下面展示我自己的配置

    1. <?xml version="1.0" encoding="UTF-8"?>
    2. <beans xmlns="http://www.springframework.org/schema/beans"
    3. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
    4. xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
    5. xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:mvc="http://www.springframework.org/schema/mvc"
    6. xmlns:util="http://www.springframework.org/schema/util"
    7. xsi:schemaLocation="http://www.springframework.org/schema/beans
    8. http://www.springframework.org/schema/beans/spring-beans.xsd
    9. http://www.springframework.org/schema/tx
    10. http://www.springframework.org/schema/tx/spring-tx.xsd
    11. http://www.springframework.org/schema/context
    12. http://www.springframework.org/schema/context/spring-context.xsd
    13. http://www.springframework.org/schema/aop
    14. http://www.springframework.org/schema/aop/spring-aop.xsd
    15. http://www.springframework.org/schema/jdbc
    16. http://www.springframework.org/schema/jdbc/spring-jdbc-3.2.xsd
    17. http://www.springframework.org/schema/util
    18. http://www.springframework.org/schema/util/spring-util-3.2.xsd
    19. http://www.springframework.org/schema/mvc
    20. http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd">
    21. <!-- spring自动扫描注解的组件 -->
    22. <context:component-scan base-package="cn.xx.xx"
    23. use-default-filters="false">
    24. <context:include-filter expression="org.springframework.stereotype.Controller"
    25. type="annotation" />
    26. </context:component-scan>
    27. <mvc:annotation-driven>
    28. <mvc:message-converters>
    29. <ref bean="stringHttpMessageConverter" />
    30. <ref bean="fastJsonHttpMessageConverter" />
    31. <ref bean="marshallingHttpMessageConverter" />
    32. </mvc:message-converters>
    33. </mvc:annotation-driven>
    34. <bean id="stringHttpMessageConverter"
    35. class="org.springframework.http.converter.StringHttpMessageConverter">
    36. <constructor-arg value="UTF-8" index="0"></constructor-arg><!--
    37. 避免出现乱码 -->
    38. <property name="supportedMediaTypes">
    39. <list>
    40. <value>text/plain;charset=UTF-8</value>
    41. </list>
    42. </property>
    43. </bean>
    44. <bean id="fastJsonHttpMessageConverter"
    45. class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
    46. <property name="supportedMediaTypes">
    47. <list>
    48. <value>application/json;charset=UTF-8</value>
    49. <value>text/html;charset=UTF-8</value><!-- 避免IE出现下载JSON文件的情况 -->
    50. </list>
    51. </property>
    52. <property name="features">
    53. <util:list>
    54. <!-- <value>WriteMapNullValue</value> -->
    55. <value>QuoteFieldNames</value>
    56. <value>WriteDateUseDateFormat</value>
    57. </util:list>
    58. </property>
    59. </bean>
    60. <bean id="marshallingHttpMessageConverter"
    61. class="org.springframework.http.converter.xml.MarshallingHttpMessageConverter">
    62. <property name="marshaller" ref="castorMarshaller" />
    63. <property name="unmarshaller" ref="castorMarshaller" />
    64. <property name="supportedMediaTypes">
    65. <list>
    66. <value>text/xml;charset=UTF-8</value>
    67. <value>application/xml;charset=UTF-8</value>
    68. </list>
    69. </property>
    70. </bean>
    71. <!-- 返回类型定义 -->
    72. <util:list id="messageConverters">
    73. <ref bean="stringHttpMessageConverter" />
    74. <ref bean="fastJsonHttpMessageConverter" />
    75. <ref bean="marshallingHttpMessageConverter" />
    76. </util:list>
    77. <bean id="castorMarshaller" class="org.springframework.oxm.castor.CastorMarshaller" />
    78. <!-- AOP自动注解功能 -->
    79. <aop:aspectj-autoproxy />
    80. <!-- 不进行拦截的 -->
    81. <mvc:resources location="/" mapping="/**/*.html" order="0" />
    82. <mvc:resources location="/images/" mapping="/images/**" />
    83. <mvc:resources location="/img/" mapping="/img/**" />
    84. <mvc:resources location="/download/" mapping="/download/**" />
    85. <mvc:resources location="/js/" mapping="/js/**" />
    86. <mvc:resources location="/css/" mapping="/css/**" />
    87. <mvc:resources location="/plugin/" mapping="/plugin/**" />
    88. <mvc:resources location="/WEB-INF/pages/" mapping="/pages/**" />
    89. <bean id="messageSource"
    90. class="org.springframework.context.support.ResourceBundleMessageSource">
    91. <property name="basename" value="messages"></property>
    92. </bean>
    93. <bean
    94. class="org.springframework.web.servlet.view.InternalResourceViewResolver">
    95. <property name="prefix" value="/WEB-INF/pages/" />
    96. <property name="suffix" value=".jsp" />
    97. </bean>
    98. <!-- 支持上传文件 -->
    99. <bean id="multipartResolver"
    100. class="org.springframework.web.multipart.commons.CommonsMultipartResolver" />
    101. <!-- restTemplate -->
    102. <bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
    103. <property name="messageConverters" ref="messageConverters">
    104. </property>
    105. </bean>
    106. </beans>

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