spring boot 实现文件下载

html 代码 js部分<br> window.location.href= this.Baseurl+'/plan/down?file='+filename;

spring  boot 后台代码
@GetMapping("/down")
    public HttpServletResponse   down(HttpServletResponse response,
                         HttpServletRequest request,@RequestParam("file") String files ) {
        String fileName = files;// 设置文件名，根据业务需要替换成要下载的文件名
        if (fileName != null) {
            //设置文件路径
            String pahre=System.getProperty("user.dir")+ "\\report\\";
            File file = new File(pahre , fileName);
            if (file.exists()) {
                response.setContentType("application/force-download");// 设置强制下载不打开
                response.addHeader("Content-Disposition", "attachment;fileName=" + fileName);// 设置文件名
                byte[] buffer = new byte[1024];
                FileInputStream fis = null;
                BufferedInputStream bis = null;
                try {
                    fis = new FileInputStream(file);
                    bis = new BufferedInputStream(fis);
                    OutputStream os = response.getOutputStream();
                    int i = bis.read(buffer);
                    while (i != -1) {
                        os.write(buffer, 0, i);
                        i = bis.read(buffer);
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (bis != null) {
                        try {
                            bis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if (fis != null) {
                        try {
                            fis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
        return null;
    }