springboot 下载 Excel 文件的 Controller 层案例

环境 pom.xml 中 springboot版本：

    <parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.7.15</version></parent>

Excel 文件依赖：

<!-- POI --><dependency><groupId>org.apache.poi</groupId><artifactId>poi</artifactId><version>4.1.2</version></dependency><dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml</artifactId><version>4.1.2</version></dependency><dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml-schemas</artifactId><version>4.1.2</version></dependency><dependency><groupId>org.apache.poi</groupId><artifactId>ooxml-schemas</artifactId><version>1.1</version></dependency>

demo1

    // 下载 Excel@GetMapping(value = "/downloadData")public ResponseEntity<byte[]> downloadData2(@RequestParam("id") String id) throws IOException {log.info("---------------downloadData start-------------");String rootDirectory = request.getServletContext().getRealPath("/");log.info("rootDirectory:"+rootDirectory);// 临时放置文件目录Path p = Paths.get(rootDirectory, "temp");if (!p.toFile().exists()) {p.toFile().mkdirs();}log.info("---------------downloadData start 2 Render.... -------------");// 写 业务逻辑，生成 Excel FileFile file = null; log.info("###------------the excel file address:"+file.getAbsolutePath());// 下载成功返回二进制流return getResponseEntity(file,null,false);}private static ResponseEntity<byte[]> getResponseEntity(File file,String userAgent,boolean inline) throws IOException {ResponseEntity.BodyBuilder bodyBuilder = ResponseEntity.ok();bodyBuilder.contentLength(file.length());// 二进制数据流
//        bodyBuilder.contentType(MediaType.APPLICATION_OCTET_STREAM);// 文件名编码String encodeFileName = URLEncoder.encode(file.getName(), "UTF-8");// IEif (userAgent!=null&&userAgent.indexOf("MSIE") > 0) {bodyBuilder.header("Content-Disposition", "attachment;filename=" + encodeFileName);} else { // 其他浏览器if (inline) {// 在浏览器中直接打开URL url = new URL("file:///" + file);bodyBuilder.header("Content-Type", url.openConnection().getContentType());bodyBuilder.header("Content-Disposition", "inline;filename*=" + encodeFileName);} else {// 直接下载bodyBuilder.header("Content-Disposition", "attachment;filename*=" + encodeFileName);bodyBuilder.header("Content-Type","application/vnd.ms-excel;charset=utf8");}}// 下载成功返回二进制流return bodyBuilder.body(Files.readAllBytes(file.toPath()));}

demo2

    @GetMapping(value = "/download2")public void download2(@RequestParam("id") String id,@RequestParam(required = false, defaultValue = "false") @ApiParam("参数 inline表示是否要在线浏览，true是，false否(默认).") boolean inline,@RequestHeader("user-agent") @ApiParam("参数userAgent 是为了兼容IE判断，如果使用谷歌，火狐浏览器就可以省略这个参数.") String userAgent,ServletRequest request,HttpServletResponse response) throws IOException {String rootDirectory = request.getServletContext().getRealPath("/");
//        System.out.println("rootDirectory:"+rootDirectory);// 临时放置文件目录Path p = Paths.get(rootDirectory, "temp");if (!p.toFile().exists()) {p.toFile().mkdirs();}// 根据业务生成 文件File file = new File("");this.download(response,file,null);}private void download(HttpServletResponse response, File file, String fileName){if(fileName==null){fileName = file.getName();}try(FileInputStream is = new FileInputStream(file);OutputStream os = response.getOutputStream()) {//通用的mime类型response.setContentType("application/octet-stream");response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName,"UTF-8"));byte[] buf = new byte[1024];int len = 0;while((len = is.read(buf))!=-1){os.write(buf,0,len);}}catch (Exception e) {throw new RuntimeException(e);}}