下载文件 不想生成临时文件

        String fileName = "configKV.json";
        //获取的String 文件
        String downConfFile = configManagerService.downConfFile();
        System.out.println(downConfFile.substring(downConfFile.length()-50,downConfFile.length()));
        //response.setContentType("application/octet-stream");
        response.addHeader("Content-Type", "application/octet-stream");
        //这里长度不要写成downConfFile.length()  容易丢失数据
        response.addHeader("Content-Length", "" + downConfFile.getBytes().length);
        response.addHeader("Content-Disposition", "attachment;filename=" + fileName);
        //byte[] buffer = new byte[BUFFER_SIZE];
        int BUFFER_SIZE = 4096; // 缓冲区大小，根据需要调整
        byte[] buffer = new byte[BUFFER_SIZE];


        try (OutputStream outputStream = response.getOutputStream();
             ByteArrayInputStream inputStream = new ByteArrayInputStream(downConfFile.getBytes())) {
            int bytesRead;
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }
            outputStream.flush();
        } catch (IOException e) {
            throw new MeshException("文件下载失败");
        } finally {
            try {
                response.getOutputStream().close();
            }catch (IOException ioException){
                throw new MeshException("文件下载失败");
            }

        }