The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler-蒲公英云

The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler

今天使用Spring mvc 尝试文件的上传下载，URL 访问的时候，报如下错误:

Type Exception Report
Message No adapter for handler [com.cbss.FileUploadController@16d4015]: The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler
Description The server encountered an unexpected condition that prevented it from fulfilling the request.
Exception
javax.servlet.ServletException: No adapter for handler [com.cbss.FileUploadController@16d4015]: The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler
    org.springframework.web.servlet.DispatcherServlet.getHandlerAdapter(DispatcherServlet.java:1202)
    org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:947)
    org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:901)
    org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
    org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:635)
    org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:742)
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
Note The full stack trace of the root cause is available in the server logs.

经过核查，发现原因如下，Spring 上下文配置文件没有如下配置，可能导致注解没有生效

<mvc:annotation-driven />

完整的applicationContext.xml内容如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
                           http://www.springframework.org/schema/mvc
                           http://www.springframework.org/schema/mvc/spring-mvc-4.2.xsd">
    <context:component-scan base-package="com.cbss" />
    <mvc:annotation-driven />
<!--    <!– 配置视图解析器 –>
    <bean id="viewResolver"
          class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/page/"></property>
        <property name="suffix" value=".jsp"></property>
    </bean>-->
    <!--用于将对象转换成json-->
    <bean id="stringConverter" class="org.springframework.http.converter.StringHttpMessageConverter">
        <property name="supportedMediaTypes">
            <list>
                <value>text/plain;charset=UTF-8</value>
            </list>
        </property>
    </bean>
    <bean id="jsonConverter"
          class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
    </bean>
    <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
        <property name="messageConverters">
            <list>
                <ref bean="stringConverter"/>
                <ref bean="jsonConverter"/>
            </list>
        </property>
    </bean>
    <bean id="multipartResolver"
          class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
        <!--上传文件的最大大小-->
        <property name="maxUploadSize" value="17367648787"></property>
        <!-- 上传文件的编码 -->
        <property name="defaultEncoding" value="UTF-8"></property>
    </bean>
</beans>