Srpin Boot实现文件下载

@RequestMapping("download")
public String download(HttpServletRequest request, HttpServletResponse response) throws IOException {

    String fileName = "D:\\exce\\aaaa\\xxlJobWsdl.xls";
    if (fileName != null) {
        //当前是从该工程的WEB-INF//File//下获取文件(该目录可以在下面一行代码配置)然后下载到C:\\users\\downloads即本机的默认下载的目录
        String realPath = request.getServletContext().getRealPath(
                "D:\\exce\\aaaa\\");
        File file = new File(realPath, 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);
                }
                System.out.println("success");
            } 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;
}