java文件复制，文件下载

1. 下载文件

public void exportOpenFile(HttpServletResponse response) {
        // 通过工具类创建writer
        FileInputStream fis = null;
        ServletOutputStream sos = null;
        try {
            //设置响应头
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
            response.setHeader("Content-Disposition", "attachment;filename=ems_info_upload_and_print_zj_open.xlsx");
            String path = "/ems_info_upload_and_print_zj_open.xlsx";
            fis = new FileInputStream(this.getClass().getResource(path).getFile());
            sos = response.getOutputStream();
            IOUtils.copy(fis, sos);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException("模板下载失败！");
        } finally {
            try {
                if (fis != null) {
                    fis.close();
                }
                if (sos != null) {
                    sos.flush();
                    sos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

2. 复制文件

 public AjaxResult importFile(MultipartFile file) {try {
            // 存储excel文件
            Calendar calendar = Calendar.getInstance();
            String fileFolderYear = String.valueOf(calendar.get(Calendar.YEAR));
            String fileFolderMonth = String.valueOf(calendar.get(Calendar.MONTH) + 1);
            String fileFolderDay = String.valueOf(calendar.get(Calendar.DATE));
            // 得到工程保存文件的路径
            String filePath = getSession().getServletContext()
                    .getRealPath("/" + "file" + "/ems_info_upload_print/" + fileFolderYear + "/"
                            + fileFolderMonth + "/" + fileFolderDay + "/" + userId + "/")
                    + "/";
            File file1 = new File(filePath);
            if (!file1.exists()) {
                file1.mkdirs();
            }
            InputStream is2 = file.getInputStream();
            // 文件大小
            int fileSize = is2.available();
            // 得到文件保存的位置(根据root来得到文件保存的路径在tomcat下的该工程里)
            String fileUuidName = IdUtil.simpleUUID() + "." + "xls";
            File excelFile = new File(filePath, fileUuidName);

            // 把文件写入到上面设置的路径里
            OutputStream os = new FileOutputStream(excelFile);
            IOUtils.copy(is2, os);
            /*byte[] buffer = new byte[400];
            int length = 0;
            while ((length = is2.read(buffer)) > 0) {
                os.write(buffer, 0, length);
            }*/
            os.flush();
            os.close();
            is2.close();
}