inputStream转byte数组

转载自：https://blog.csdn.net/fengsheng5210/article/details/78191734，稍作修改

/**
     * inputStream转byte数组
     *
     * @param inputStream 输入流对象
     * @return byte数组
     */
    public static byte[] inputStreamToByteArray(InputStream inputStream) {
        try (ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream()) {
            byte[] buffer = new byte[1024];
            int num;
            while ((num = inputStream.read(buffer)) != -1) {
                byteArrayOutputStream.write(buffer, 0, num);
            }
            byteArrayOutputStream.flush();
            return byteArrayOutputStream.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return new byte[]{};
    }