使用了springmvc+velocity的项目，返回json出现了问题
问题描述：
出现了406错误
找不到要解析成的头部！
问题原因：
缺少json转换配置
解决办法：
在对应的servlet配置文件中添加
xmlns:mvc="http://www.springframework.org/schema/mvc"
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<mvc:annotation-driven>
<mvc:message-converters register-defaults="false">
<bean class="org.springframework.http.converter.BufferedImageHttpMessageConverter"/>
<bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter"/>
<bean class="org.springframework.http.converter.StringHttpMessageConverter"/>
<bean class="org.springframework.http.converter.support.AllEncompassingFormHttpMessageConverter"/>
<bean class="org.springframework.http.converter.xml.SourceHttpMessageConverter"/>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="supportedMediaTypes">
<list>
<value>text/html;charset=UTF-8</value>
<value>application/json;charset=UTF-8</value>
<value>application/*+json;charset=UTF-8</value>
</list>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>