导出

通过生成File，达到下载文件的目的

public R exportCsv(@RequestBody String[] ids, HttpServletResponse response) {
    logger.info("导出");
    try {
        File file = xxxService.exportCsv(ids);
        // 设置Content-Disposition
        response.addHeader("Access-Control-Expose-Headers", "Content-Disposition");
        response.addHeader("Content-Disposition", "attachment;filename=" + file.getName());
        InputStream in = new FileInputStream(file.getPath());
        OutputStream out = response.getOutputStream();
        int b;
        while ((b = in.read()) != -1) {
            out.write(b);
        }
        out.close();
        in.close();
        // 删除生成的文件
        xxxService.deleteFile(file);
    } catch (Exception e) {
        e.printStackTrace();
        logger.error("导出文件失败", e);
    }
    return null;
}