下载网络图片并上传微信公众平台素材库

最近在做微信公众号相关功能，需要把网络图片上传到微信素材库。由于微信开放接口不识别网络图片地址，需要把图片先下载到服务器再上传，废话不多说，直接上代码：

@Override
    public JSONObject uploadImg2WXTemp(String imgPath, String appId) throws Exception {
    	//调用微信接口获取accessToken
        String accessToken = getAccessToken(appId);
        
        RestTemplate restTemplate = new RestTemplate();
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.MULTIPART_FORM_DATA);
        URL url = new URL(imgPath);
        //打开链接
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        //设置请求方式为"GET"
        conn.setRequestMethod("GET");
        //超时响应时间为5秒
        conn.setConnectTimeout(5 * 1000);
        InputStream inStream = null;
        FileOutputStream outStream = null;
        try {
            //通过输入流获取图片数据
            inStream = conn.getInputStream();
            //得到图片的二进制数据，以二进制封装得到数据，具有通用性
            byte[] data = readInputStream(inStream);
            //这个判断可以删掉，是为了兼容业务图片
            if (imgPath.contains("?")){
                imgPath = imgPath.split("\\?")[0];
            }

            String fileExtend = imgPath.substring(imgPath.lastIndexOf(".") + 1);
            LocalDate now = LocalDate.now();
            //文件命名随意
            String filePath = "material_" + now.getYear() + "_" + now.getMonthValue() + "_" + now.getDayOfMonth()+"_"+System.currentTimeMillis()+ "." + fileExtend;
            File imageFile = new File(filePath);
            //创建输出流
            outStream = new FileOutputStream(imageFile);
            //写入数据
            outStream.write(data);

            MultiValueMap<String, Object> multiValueMap = new LinkedMultiValueMap<>();
            multiValueMap.add("media", new FileSystemResource(imageFile));
            multiValueMap.add("filename", filePath);
            multiValueMap.add("filelength", data.length);
            String mediaType = "";
            //可以查看微信公众平台文档，可以上传哪些类型图片和图片大小限制
            switch (fileExtend) {
                case "jpg":
                    mediaType = MediaType.IMAGE_JPEG_VALUE;
                    break;
                case "png":
                    mediaType = MediaType.IMAGE_PNG_VALUE;
                    break;
                case "jpeg":
                    mediaType = MediaType.IMAGE_JPEG_VALUE;
                    break;
                default:
                    throw new Exception("请检查图片格式");

            }
            multiValueMap.add("content-type", mediaType);
            HttpEntity<MultiValueMap<String, Object>> httpEntity = new HttpEntity<>(multiValueMap, headers);
            //uploadTempUrl根据自己需求定义
            ResponseEntity<String> responseEntity = restTemplate.postForEntity(
                    uploadTempUrl + "?access_token={access_token}&type=image", httpEntity, String.class, accessToken);
            LogUtil.logApplicationInfo("上传微信临时素材："+JSON.toJSONString(responseEntity));
            boolean delete = imageFile.delete();
            if (!delete) {
                LogUtil.logApplicationInfo("删除下载图片报错");
            }
            if (HttpStatus.OK.value() != responseEntity.getStatusCodeValue()) {
                LogUtil.logApplicationError(
                        String.format("调用微信新增素材接口失败，result:{%s}", JSON.toJSONString(responseEntity)));
                return null;
            }
            //删除图片
            return JSON.parseObject(responseEntity.getBody());
        } finally {
            if (Objects.nonNull(inStream)) {
                inStream.close();
            }
            if (Objects.nonNull(outStream)) {
                outStream.close();
            }
        }
    }

	
	private static byte[] readInputStream(InputStream inStream) throws Exception {
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        //创建一个Buffer字符串
        byte[] buffer = new byte[1024 * 4];
        //每次读取的字符串长度，如果为-1，代表全部读取完毕
        int len;
        //使用一个输入流从buffer里把数据读取出来
        while ((len = inStream.read(buffer)) != -1) {
            //用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度
            outStream.write(buffer, 0, len);
        }
        //关闭输入流
        inStream.close();
        //把outStream里的数据写入内存
        return outStream.toByteArray();
    }