uploadUrl: '/file/weChatMsgUpload', //上传的地址

    /**
     * 群发消息上传
     * 群发消息上传成功后无法区分文件类型，故需要在上传成功后返回文件类型
     */
    @PostMapping("/file/weChatMsgUpload")
    @ResponseBody
    public AjaxResult weChatMsgUpload(MultipartFile file){
        try
        {
            WeChatUploadAttachmentResponse res = weChatService.uploadMsg(file);
            if (res != null) {
                AjaxResult ajax = AjaxResult.success();
                ajax.put("fileName", file.getOriginalFilename());
                ajax.put("url", res.getType()+"@"+res.getMediaId());
                return ajax;
            }else {
                return AjaxResult.error("上传失败！");
            }
        }
        catch (Exception e)
        {
            return AjaxResult.error(e.getMessage());
        }
    }

    /**
     * 上传临时素材--群发消息
     * https://developer.work.weixin.qq.com/document/path/90253
     *  素材上传得到media_id，该media_id仅三天内有效
     *   media_id在同一企业内应用之间可以共享
     * 媒体文件类型，分别有图片（image）、语音（voice）、视频（video），普通文件(file)
     * @param file
     * @return
     */
    @Override
    public WeChatUploadAttachmentResponse uploadMsg(MultipartFile file) {
        //获取accesstoken
        String accessToken = getAccessToken();
        if (StringUtils.isNotEmpty(accessToken)) {
      //获取原始上传文件名称
            String filename = file.getOriginalFilename();
            //获取后缀 'jpg','JPG','png','PNG','mp4','MP4'
            //,'amr','AMR','txt','pdf','PDF','xlx','xlxs','doc','docx'
            int i = filename.lastIndexOf(".");
            String substring = filename.substring(i + 1);
            String mediaType = "";
            if ("jpg".equals(substring) || "JPG".equals(substring) || "png".equals(substring) || "PNG".equals(substring)) {
                mediaType = "image";
            }else if ("mp4".equals(substring) || "MP4".equals(substring)) {
                mediaType = "video";
            }else if ("amr".equals(substring) || "AMR".equals(substring)) {
                mediaType = "voice";
            }else {
                mediaType = "file";
            }
      //上传临时素材接口地址
            String url = "https://qyapi.weixin.qq.com/cgi-bin/media/upload?access_token="+accessToken+
                    "&type="+mediaType;
      //设置请求头信息
            HttpHeaders headers = new HttpHeaders();
            headers.setContentType(MediaType.MULTIPART_FORM_DATA);
            File file1 = null;
            try {
        //设置文件大小
                int length = file.getBytes().length;
                headers.setContentLength(length);
        //设置请求包Content-Disposition  form-data中媒体文件标识
                ContentDisposition contentDisposition =
                        ContentDisposition.builder("form-data").filename(filename).name("media").build();
                headers.setContentDisposition(contentDisposition);
        //MultipartFile 转 File
                file1 = toFile(file);
        //获取FileSystemResource
                FileSystemResource resource = new FileSystemResource(file1);
                MultiValueMap<String, Object> params = new LinkedMultiValueMap<>();
                params.add("media", resource);
        //设置请求包
                HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(params, headers);
        //post调用企业微信上传临时素材接口
                ResponseEntity<String> post = RestUtils.post(url,requestEntity,String.class);
                if (Objects.nonNull(post)) {
          //获取返回值
                    String body = post.getBody();
                    WeChatUploadAttachmentResponse res = JSON.parseObject(body, WeChatUploadAttachmentResponse.class);
                    return res;
                }
            }catch (Exception e) {
                e.printStackTrace();
            }finally {
                if (file1 != null) {
                    file1.delete();
                }
            }
        }
        return null;
    }
  //MultipartFile  转 File
    private File toFile(MultipartFile multipartFile) {
        //文件上传前的名称
        String fileName = multipartFile.getOriginalFilename();
        File file = new File(fileName);
        OutputStream out = null;
        try{
            //获取文件流，以文件流的方式输出到新文件
            out = new FileOutputStream(file);
            byte[] ss = multipartFile.getBytes();
            for(int i = 0; i < ss.length; i++){
                out.write(ss[i]);
            }
            return file;
        }catch(IOException e){
            e.printStackTrace();
            return null;
        }finally {
            if (out != null){
                try {
                    out.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

public class WeChatUploadAttachmentResponse extends WeChatResponse{
    private static final long serialVersionUID = -6462589895169294923L;
    @ApiField("type")
    private String type;
    @ApiField("media_id")
    private String mediaId;
    @ApiField("created_at")
    private Long createdAt;
    public String getType() {
        return type;
    }
    public void setType(String type) {
        this.type = type;
    }
    public String getMediaId() {
        return mediaId;
    }
    public void setMediaId(String mediaId) {
        this.mediaId = mediaId;
    }
    public Long getCreatedAt() {
        return createdAt;
    }
    public void setCreatedAt(Long createdAt) {
        this.createdAt = createdAt;
    }
}