Spring MVC：HTTP状态400-必需的MultipartFile参数'file'不存在

Question

这是我的控制器：

@RequestMapping(value = "/admin/users/photo", method = RequestMethod.POST)
public ModelAndView editUser(@RequestParam("file") MultipartFile file,
                             Principal principal) {
    // code never gets here
}

我的mvc-dispatcher-servlet.xml

<bean id="multipartResolver"
      class="org.springframework.web.multipart.support.StandardServletMultipartResolver">
</bean>

pom.xml：

    <dependency>
        <groupId>commons-fileupload</groupId>
        <artifactId>commons-fileupload</artifactId>
        <version>1.3.1</version>
    </dependency>

形式本身：

<form action="${pageContext.request.contextPath}"
      method="POST"
      enctype="multipart/form-data">
        <input type="file"
        name="file"
        />
    <input type="submit" value="Добавить">
</form>

这是浏览器说的：

如何解决？

Answer 1

您可以尝试使用此

<bean id="multipartResolver" class="**org.springframework.web.multipart.commons.CommonsMultipartResolver**" />

代替

<bean id="multipartResolver"
      class="org.springframework.web.multipart.support.StandardServletMultipartResolver">

Answer 2

Servlet 3.0规范。

StandardServletMultipartResolver是{@link MultipartResolver}接口的标准实现

http://grepcode.com/file/repo1.maven.org/maven2/org.springframework/spring-web/4.1.1.RELEASE/org/springframework/web/multipart/support/StandardServletMultipartResolver.java#StandardServletMultipartResolver