springboot实现下载文件，并且在下载完成删除文件

/**
     * 下载文件
     */
    @ApiOperation(value = "下载文件", notes = "下载文件")
    @PostMapping(value = "/contract/download", produces = "application/json;charset=UTF-8")
    public void contractDownload(HttpServletResponse response, @RequestBody X2ContractDownloadRequest req) {
        try {
            // 获取远程文件
            Path filePath = iQiyuesuoSdkService.contractDownload(req);

            // 设置响应头
            response.setContentType("application/octet-stream");
            response.setHeader("Content-Disposition", "attachment;filename=\"" + filePath.getFileName().toString() + "\"");

            // 分段下载
            int BUFFER_SIZE = 1024 * 100; // 100KB
            try (FileInputStream fis = new FileInputStream(filePath.toFile());
                 BufferedInputStream bis = new BufferedInputStream(fis);
                 ServletOutputStream sos = response.getOutputStream()) {
                byte[] buffer = new byte[BUFFER_SIZE];
                int bytesRead;
                while ((bytesRead = bis.read(buffer)) != -1) {
                    sos.write(buffer, 0, bytesRead);
                }
            }

            // 删除文件
            Files.delete(filePath.toFile().toPath());
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }