springmvc框架下Filter过滤器中过滤文件后 后续 controller为空的问题

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        String contentType = request.getContentType();
        
        if(null != contentType && contentType.contains("multipart/form-data")){//说明是文件上传
        
            CommonsMultipartResolver commonsMultipartResolver = new CommonsMultipartResolver();
            MultipartHttpServletRequest resolveMultipart = commonsMultipartResolver.resolveMultipart(req);        
            boolean b = true;
                 Map<String, MultipartFile> fileMap = resolveMultipart.getFileMap();
                 for (String key : fileMap.keySet()) {
                     MultipartFile multipartFile = fileMap.get(key);
                            InputStream is = multipartFile.getInputStream();
                           //你的过滤逻辑
                                    b=false;
                                }
                       }
                    }        
            if(b){
                chain.doFilter(resolveMultipart, response);
            }
        }else{
            chain.doFilter(request, response);
        }
        
    }