14 springboot文件下载

Posted 2020-12-15 孤芳不自赏!

文件下载特别简单，给个文件路径，输出个流即可。

controller

    @GetMapping(value = "/download")
    @IgnoreUserToken
    public void downLoad(String id, HttpServletResponse response){
        Template template = templateBiz.selectById(id);
        String templatePath = template.getTemplatePath();
        String templateName = template.getTemplateName();
        try {
            //绝对路径
            String targetFile = templatePath + "/" + templateName;
            response.setCharacterEncoding("utf-8");
            response.setContentType("multipart/form-data");
            response.setHeader("Content-Disposition","attachment;fileName=" + FileUtils.setFileDownloadHeader(request, templateName));
            FileUtils.writeBytes(targetFile, response.getOutputStream());
        } catch (Exception e) {
            log.error("下载文件失败", e);
        }

    }

FileUtils中，对下载的文件名重新编码（setFileDownloadHeader）

    /**
     * 下载文件名重新编码
     *
     * @param request  请求对象
     * @param fileName 文件名
     * @return 编码后的文件名
     */
    public static String setFileDownloadHeader(HttpServletRequest request, String fileName)
            throws UnsupportedEncodingException {
        final String agent = request.getHeader("USER-AGENT");
        String filename = fileName;
        if (agent.contains("MSIE")) {
            // IE浏览器
            filename = URLEncoder.encode(filename, "utf-8");
            filename = filename.replace("+", " ");
        } else if (agent.contains("Firefox")) {
            // 火狐浏览器
            filename = new String(fileName.getBytes(), "ISO8859-1");
        } else if (agent.contains("Chrome")) {
            // google浏览器
            filename = URLEncoder.encode(filename, "utf-8");
        } else {
            // 其它浏览器
            filename = URLEncoder.encode(filename, "utf-8");
        }
        return filename;
    }　

FileUtis中读取文件流（writeBytes）

    /**
     * 输出指定文件的byte数组
     *
     * @param filePath 文件路径
     * @param os       输出流
     * @return
     */
    public static void writeBytes(String filePath, OutputStream os) throws IOException {
        FileInputStream fis = null;
        try {
            File file = new File(filePath);
            if (!file.exists()) {
                throw new FileNotFoundException(filePath);
            }
            fis = new FileInputStream(file);
            byte[] b = new byte[1024];
            int length;
            while ((length = fis.read(b)) > 0) {
                os.write(b, 0, length);
            }
        } catch (IOException e) {
            throw e;
        } finally {
            if (os != null) {
                try {
                    os.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
        }
    }

　至此ok。