public UploadTempMediaResult uploadMedia(String accessToken, String type, File file) {
        log.info("把媒体文件上传到微信服务器[OkHttpClient] 请求参数 type[{}] filename[{}]", type, file.getName());
        try {
            OkHttpClient client = new OkHttpClient().newBuilder()
                    .build();
//            MediaType mediaType = MediaType.parse("text/plain");
            RequestBody body = new MultipartBody.Builder().setType(MultipartBody.FORM)
                    .addFormDataPart("media", file.getName(),
                            RequestBody.create(MediaType.parse("application/octet-stream"),
                                    file
                            )
                    )
                    .build();
            String url = String.format("https://api.weixin.qq.com/cgi-bin/media/upload?access_token=%s&type=%s", accessToken, type);
            Request request = new Request.Builder()
                    .url(url)
                    .method("POST", body)
                    .build();
            Response response = client.newCall(request).execute();
            ResponseBody responseBody = response.body();
            if (responseBody == null) {
                return null;
            }
            UploadTempMediaResult uploadTempMediaResult = JSONObject.parseObject(responseBody.string(), UploadTempMediaResult.class);
            log.info("把媒体文件上传到微信服务器[OkHttpClient] 返回结果 {}", JSONObject.toJSONString(uploadTempMediaResult));

            return uploadTempMediaResult;
        } catch (Exception e) {
            log.info("uploadMedia e = ", e);
        }

        return null;
    }

我的RestTemplate 上传没问题