spring jar包状态下 resource文件夹的资源下载为空文件损坏问题_springboot 从resource下载文件 服务器端空的

公司有个需求是下载excel的模板文件，我将excel文件放在了resouece资源文件夹下，通过文件流读取并写入到response流当中，调试接口文件能下载一切正常。后面打成jar包上到服务环境之后，下载的excel体积为0kb 并且打开之后显示文件是损坏的。后面通过将resouece资源文件夹下的文件先暂存到一个临时文件中，再读取临时文件的流解决了这个损坏文件的问题。

 public void downLoadTemplate(HttpServletResponse response, HttpServletRequest request) throws IOException {
        String fileName = "机构导入模板.xlsx";
        ClassPathResource classPathResource = new ClassPathResource("/excel/机构导入模板.xlsx");
        InputStream inputStream = classPathResource.getInputStream();
        //生成目标文件
        File somethingFile = File.createTempFile("Topic_Template", ".xlsx");
        try {
            FileUtils.copyInputStreamToFile(inputStream, somethingFile);
        } finally {
            IOUtils.closeQuietly(inputStream);
        }
        InputStream in = new FileInputStream(somethingFile);
        FileDownLoadUtil.getFileContent(in, fileName, response, request);
    }

 public static  void getFileContent(InputStream inputStream, String name, HttpServletResponse response, HttpServletRequest request) {
        // 清空response
        response.reset();
        try {
            InputStream in = inputStream;
            response.setHeader("Content-Length", String.valueOf(in.available()));
            byte[] buffer = new byte[in.available()];
            //不加打开会文件损坏
            in.read(buffer);
            in.close();
            String userAgent = request.getHeader("User-Agent");
            String fileName;
            if (userAgent.contains("MSIE") || userAgent.contains("Trident")) {
                fileName = URLEncoder.encode(name, "UTF-8");
            } else {
                // 非IE浏览器的处理：
                fileName = new String(name.getBytes("UTF-8"), "ISO-8859-1");
            }
            // 设置response的Header
            response.addHeader("Content-Disposition", "attachment;filename=" + fileName);
            OutputStream toClient = new BufferedOutputStream(response.getOutputStream());
            response.setContentType("application/octet-stream");
            toClient.write(buffer);
            toClient.flush();
            toClient.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }