使用DispatcherServlet后MultipartFile接收不到文件

Question

使用DispatcherServlet

@Configuration
public class WebConfig {   
    @Bean
    public ServletRegistrationBean apiV1ServletBean(WebApplicationContext wac) {
        DispatcherServlet ds = new DispatcherServlet(wac);
        ServletRegistrationBean bean = new ServletRegistrationBean(ds, "/*");
        bean.setName("xxx");
       bean.addUrlMappings("/xxx/*");
       return bean;
   }

}

MultipartFile接收不到文件
@RequestMapping(method = RequestMethod.POST)
    public Response<String> site(@RequestParam("file") MultipartFile file, String userId, HttpServletRequest request) {

}

错误报告：
Required request part 'file' is not present

Answer 1

确定参数名称"file"对吗？
试下这样，我是这样用的没问题。

List<String> imgUrls=new ArrayList<>();
MultipartHttpServletRequest multipartRequest =(MultipartHttpServletRequest) request;
List<MultipartFile> files=multipartRequest.getFiles("file");

再加上前端的

<form action="/upload" method="post" enctype="multipart/form-data">
<input type="file" name="file" multiple>
<input type="submit" ">
</form>

Answer 2

var formData = new FormData();
formData.append('file', $('#****')[0].files[0]);

Answer 3

我今天刚好遇到这个问题，研究解决了。

这个因为你自己注入的ServletRegistrationBean跟spring boot默认注入的ServletRegistrationBean的配置不一样。你自己注入的ServletRegistrationBean默认没有配置处理上传请求的。

请参考以下配置：

    //自动注入spring boot默认的上传配置
    @Autowired
    private MultipartConfigElement multipartConfigElement;
    @Bean
    public ServletRegistrationBean apiV1ServletBean(WebApplicationContext wac) {
        DispatcherServlet servlet = new DispatcherServlet(wac);
        ServletRegistrationBean bean = new ServletRegistrationBean(servlet, "/api/*");
        //注入上传配置到自己注册的ServletRegistrationBean
        bean.setMultipartConfig(multipartConfigElement);
        bean.setName("ApiServlet");
        return bean;
    }