使用EasyExcel下载文件时，前端获取不到后端返回的文件名，无法下载到本地

【问题描述】

使用EasyExcel下载文件时，前端获取不到后端返回的文件名，无法下载到本地

【原因分析】

实际上文件的流后端已经返回了，只是缺少了Content-Disposition属性返回，前端无法获取到文件名；

private static OutputStream getOutputStream(String fileName, HttpServletResponse response) throws Exception {
fileName = URLEncoder.encode(fileName, "UTF-8");
response.setContentType("application/vnd.ms-excel; charset=utf-8");
response.setCharacterEncoding("utf-8");
response.setHeader("Content-Disposition", "attachment;filename=" + fileName + ".xlsx");
return response.getOutputStream();
}

【解决方案】

需要增加下面这行，后端才能够返回文件名称给前端，前端才可以下载：

response.addHeader("Access-Control-Expose-Headers", "Content-Disposition");

private static OutputStream getOutputStream(String fileName, HttpServletResponse response) throws Exception {

　　fileName = URLEncoder.encode(fileName, "UTF-8");
　　response.setContentType("application/vnd.ms-excel; charset=utf-8");
　　response.setCharacterEncoding("utf-8");
　　response.addHeader("Access-Control-Expose-Headers", "Content-Disposition");
　　response.setHeader("Content-Disposition", "attachment;filename=" + fileName + ".xlsx");
　　return response.getOutputStream();
}