@Slf4j
@Component
public class CustomerService {
    private static final String UPLOAD_URL = "https://api.weixin.qq.com/cgi-bin/media/upload?access_token" +
            "=%s&type=image";

    @Autowired
    private RestTemplate restTemplate;
    @Autowired
    private AccessTokenHelper accessTokenHelper;


    /**
     * 把媒体文件上传到微信服务器,获取上传图片的media_id
     *
     * @return 上传图片的media_id
     */
    public String uploadTempMedia(MultipartFile file) throws IOException {
        String accessToken = accessTokenHelper.getAccessToken();
        log.info(accessToken);
        if (StringUtils.isBlank(accessToken)) {
            log.error("access_token为空");
            return null;
        }
        String url = String.format(UPLOAD_URL, accessToken);

        MultiValueMap<String, Object> multipartRequest = new LinkedMultiValueMap<>();
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.MULTIPART_FORM_DATA);
        HttpHeaders pictureHeader = new HttpHeaders();
        pictureHeader.setContentType(MediaType.parseMediaType(Objects.requireNonNull(file.getContentType())));
        pictureHeader.setContentDispositionFormData("file", UUID.randomUUID() + ".PNG");
        HttpEntity<ByteArrayResource> picturePart = new HttpEntity<>(new ByteArrayResource(file.getBytes()),
                pictureHeader);
        multipartRequest.add("file", picturePart);
        HttpEntity<MultiValueMap<String, Object>> requestEntity = new HttpEntity<>(multipartRequest, headers);
        String result = restTemplate.postForObject(url, requestEntity, String.class);
        log.info(result);
        //{"type":"image","media_id":"TQMWXsRHEu9qHrMIiQ7VwygS1f4fDIoO4oHEbpFdAemOW56QiIEHOrCVVsHHqjBF","created_at":1615949444,"item":[]}

        if (!StringUtils.isBlank(result)) {
            JSONObject jsonObject = JSONObject.parseObject(result);
            return jsonObject.getString("media_id");
        }
        return null;
    }
}