MultipartFile对象为什么是空啊？

mvc.xml:

    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
            <property name="defaultEncoding" value="UTF-8"/>
    </bean>

jsp：

名称：
文件：

Controller
@Controller
@RequestMapping("/user")
public class UserController {

@RequestMapping(value = "quick14")
@ResponseBody  //不进行跳转，直接进行数据响应
public void save14(String username, MultipartFile uploadFile) throws IOException {;
    System.out.println(username);
    System.out.println(uploadFile);
}

}

jsp:不知道为啥变了，下面补充，希望有大佬解答

<form method="post" action="${pageContext.request.contextPath}/user/quick14">
    名称：<input type="text" name="username"><br/>
    文件：<input type="file" name="uploadFile"><br/>
    <input type="submit" value="提交">
</form>

坐标配置也是有的

<dependency>
      <groupId>commons-fileupload</groupId>
      <artifactId>commons-fileupload</artifactId>
      <version>1.4</version>
    </dependency>
    <dependency>
      <groupId>commons-io</groupId>
      <artifactId>commons-io</artifactId>
      <version>2.11.0</version>
    </dependency>