springMVC3.2 多视图解析器 java.lang.String cannot be cast to org.springframework.http.MediaType-优快云博客

本文介绍如何正确配置SpringMVC中的ContentNegotiatingViewResolver以解决mediaType报错问题。通过详细展示两种不同的配置方式，帮助开发者理解如何使用PathExtensionContentNegotiationStrategy和HeaderContentNegotiationStrategy来实现内容协商。

SpringMVC 3.2 org.springframework.web.servlet.view.ContentNegotiatingViewResolver 配置如下mediaType报错
<property name="mediaTypes">
<map>
  <entry key="pdf" value="application/pdf"/>
  <entry key="html" value="text/html"/>
  <entry key="json" value="application/json"/>
</map>
</property>
换成
<bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
 <property name="contentNegotiationManager">
<bean class="org.springframework.web.accept.ContentNegotiationManager">
<constructor-arg>
    <list>
    <!-- These are evaluated in order -->
    <!-- Is there a media type based on suffix? -->
<bean                  class="org.springframework.web.accept.PathExtensionContentNegotiationStrategy">
<constructor-arg>
    <map>
<entry key="html" value="text/html" />
<entry key="json" value="application/json" />
<entry key="pdf" value="application/pdf" />
</map>
</constructor-arg>
</bean>
<!-- Else use request header -->
<bean
            class="org.springframework.web.accept.HeaderContentNegotiationStrategy">

</bean>
</list>
</constructor-arg>
</bean>
</property>
</bean>