springboot下载文件

一、下面这种方法在本地是可以成功下载的，但是springboot打成jar包，部署到服务器就不行了，具体原因看另一篇文章：

SpringBoot项目打包成jar后读取文件的大坑

1.控制器

@ApiOperation(value = "下载导入模板")
    @GetMapping("download1")
    public void download1(HttpServletResponse response) throws Exception {
        File tem = ResourceUtils.getFile("classpath:excelTpl/carCardTemplate.xlsx");
        MyUtil.download(tem, "月租车信息导入模板", response);
    }

2.下载工具方法

public static void download(File localFile,String downName, HttpServletResponse res) throws IOException {

        String subffix = localFile.getName().substring(localFile.getName().lastIndexOf("."));

        // 设置信息给客户端不解析
        String type = new MimetypesFileTypeMap().getContentType(localFile.getName());
        // 设置contenttype，即告诉客户端所发送的数据属于什么类型
        res.setHeader("Content-type",type);
        // 设置编码
        String name = new String(downName.concat(subffix).getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1);
        // 设置扩展头，当Content-Type 的类型为要下载的类型时 , 这个信息头会告诉浏览器这个文件的名字和类型。
        res.setHeader("Content-Disposition", "attachment;filename=" + name);
        // 发送给客户端的数据
        OutputStream outputStream = res.getOutputStream();
//        byte[] buff = new byte[1024];
//        BufferedInputStream bis = null;
        // 读取filename
//        bis = new BufferedInputStream(new FileInputStream(fileTem));
//       int read = 0;
 //       while ((read = bis.read(buff)) != -1) {
 //           outputStream.write(buff, 0, read);
 //           outputStream.flush();
  //      }

        byte[] readByte = Files.readAllBytes(localFile.toPath());
        outputStream.write(readByte);
        outputStream.flush();
        outputStream.close();
    }

二、下面这种方法是通用方法

1.控制器

@ApiOperation(value = "下载导入模板")
    @GetMapping("download")
    public void download1(HttpServletResponse response) throws Exception {
        InputStream in = this.getClass().getResourceAsStream("/excelTpl/carCardimportTemp.xlsx");
        MyUtil.download(in, "月租车信息导入模板", response);
    }

2.工具方法

    public static void download(InputStream in, String downName, HttpServletResponse res) throws IOException {

        res.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
        res.setCharacterEncoding("UTF-8");
        String fileName = URLEncoder.encode(downName, "UTF-8").replaceAll("\+", "%20");
        String name = new String(fileName.concat(".xlsx").getBytes(StandardCharsets.UTF_8), StandardCharsets.ISO_8859_1);
        res.setHeader("Content-Disposition", "attachment;filename=" + name);

        OutputStream outputStream = res.getOutputStream();

      //        byte[] buff = new byte[1024];
//        BufferedInputStream bis = null;
        // 读取filename
//        bis = new BufferedInputStream(in);
//       int read = 0;
 //       while ((read = bis.read(buff)) != -1) {
 //           outputStream.write(buff, 0, read);
 //           outputStream.flush();
  //      }
        StreamUtils.copy(in,outputStream);
        outputStream.close();
    }