如何从Spring控制器创建文件保存对话框

Question

现在可以从Spring控制器下载文件，但没有对话框，文件直接保存到浏览器的下载文件夹中。我想要一个文件对话框，询问用户要保存在哪个文件夹中。如何做到这一点？代码是

@RequestMapping(value = "/export", method = RequestMethod.GET)
@ResponseBody
public ModelAndView export(HttpServletResponse response) {
    try {
        String str = "sep=tn"; // tells excel what the delimiter character should be
        Iterator<Individual> iterator = customerAccountService.getAllIndividuals().iterator();
        while(iterator.hasNext()){
            Individual individual = iterator.next();
            str = str + individual.getId() + "t" +individual.getIndividualName().getName() + "t" + individual.getAddress().getStreetName() + "n";
        }
        InputStream is = new ByteArrayInputStream(str.getBytes());
        IOUtils.copy(is, response.getOutputStream());
        response.setContentType("application/xls");
        response.setHeader("Content-Disposition","attachment; filename=Users-export.csv");
        response.flushBuffer();
    } catch (IOException ex) {
        //logger.info("Error writing file to output stream. Filename was '" + fileName + "'");
        throw new RuntimeException("IOError writing file to output stream");
    }
    ModelAndView modelAndView = new ModelAndView(ViewName.MENU);
    modelAndView.addObject(ObjectName.ADD_FORM, new LoginForm());
    return modelAndView;
}

Answer 1

您必须记住，您的Spring web应用程序是一个符合HTTP的应用程序。HTTP是一种请求-响应协议。客户端发送请求，服务器发送响应。

在您的情况下，响应将看起来像这个

HTTP/1.1 200 OK 
Content-Disposition: attachment; filename=Users-export.csv
Content-Type: application/xls
Content-Length: XYZ
<bytes goes here>

您的客户端（浏览器）将收到此消息，并使用它进行任何选择。您应该检查浏览器设置并启用Save As...提示。

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没有办法强制web应用程序发出浏览器提示。