在不暴露minio地址的前提下，使用kkfile实现文件预览，还加入token认证，提高安全性。
关于minio的安装与相关基础配置和使用，可以看博主的另一篇minio介绍文章
一、文件上传
上传服务
@Autowiredprivate MinioClient client;@Autowiredprivate MinioConfig minioConfig;public void uploadFile(MultipartFile file) throws Exception {String fileName = System.currentTimeMillis() + "-" + file.getOriginalFilename();PutObjectArgs args = PutObjectArgs.builder().bucket(minioConfig.getBucketName()).object(fileName).stream(file.getInputStream(), file.getSize(), -1).contentType(file.getContentType()).build();client.putObject(args);
}
封装接口
@PostMapping("upload")
public RestResult<SysFile> upload(MultipartFile file) {try {sysFileService.uploadFile(file);} catch (Exception e) {log.error("上传文件失败", e);return RestResult.fail(e.getMessage());}
}
二、文件下载
下载服务
@Autowiredprivate MinioClient client;@Autowiredprivate MinioConfig minioConfig;public void download(String filename, HttpServletResponse response) throws ServiceException {try {InputStream inputStream = client.getObject(GetObjectArgs.builder().bucket(minioConfig.getBucketName()).object(filename).build());// 设置响应头信息，告诉前端浏览器下载文件response.setContentType("application/octet-stream;charset=UTF-8");response.setCharacterEncoding("UTF-8");response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, "UTF-8"));// 获取输出流进行写入数据OutputStream outputStream = response.getOutputStream();// 将输入流复制到输出流byte[] buffer = new byte[4096];int bytesRead = -1;while ((bytesRead = inputStream.read(buffer)) != -1) {outputStream.write(buffer, 0, bytesRead);}// 关闭流资源inputStream.close();outputStream.close();} catch (Exception e) {log.error("文件下载失败：" + e.getMessage());throw new ServiceException("文件下载失败");}
}
封装接口
@ApiOperation("文件下载")
@GetMapping("/download/{token}/{filename}")
public void getDownload(@PathVariable("token") String token, @PathVariable("filename") String filename, HttpServletResponse response) {tokenUtils.validateToken(token);sysFileService.download(filename, response);
}
上面的接口有两个地方需要注意
@GetMapping("/download/{token}/{filename}")中filename参数必须放在最后
tokenUtils.validateToken(token);
该接口要在拦截器中放行，验证token在代码逻辑中，这里根据项目中实际场景去实现。该地址为kkfile请求
三、文件预览地址获取
文件预览地址生成服务（该服务只是获取token并拼接到文件下载地址中，不对token做验证，因为该服务的接口在请求进入前要做校验）
public String getPreviewUrl(String filename) throws UnsupportedEncodingException {ServletRequestAttributes sra = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();HttpServletRequest request = sra.getRequest();if (request ==null || StringUtils.isBlank(request.getHeader(TokenConstants.AUTHENTICATION))) {throw new ServiceException("未获取到有效token");}String previewUrl = filePreviewUrl + FileUploadUtils.base64UrlEncode(fileDownloadUrl + "/" + token + "/" + filename);return previewUrl + "&fullfilename=" + URLEncoder.encode(filename, "UTF-8");
}
FileUploadUtils中的base64UrlEncode方法
public static String base64UrlEncode(String url) throws UnsupportedEncodingException {String base64Url = Base64.getEncoder().encodeToString(url.getBytes(StandardCharsets.UTF_8));return URLEncoder.encode(base64Url, "UTF-8");
}
封装接口，获取文件预览地址
@GetMapping("/getPreviewUrl")
public RestResult<String> getPreviewUrl(String filename) throws UnsupportedEncodingException {return RestResult.ok(sysFileService.getPreviewUrl(filename));
}
测试
假设
文件服务地址为：http://file-server
kkfile服务地址为：http://kkfile-server
文件名称为：xxxx.docx
最后生成的文件预览地址为：
http://kkfile-server/onlinePreview?url=aHR0cDovLzE3Mi4xNi41MC4y....&fullfilename=xxxx.docx
其中aHR0cDovLzE3Mi4xNi41MC4y…为：
FileUploadUtils.base64UrlEncode("http://file-server" + "/" + token + "/" + filename);
