Servlet下载xml文件，不弹窗了解决办法

Servlet下载xml文件，不弹窗了
我已经读取到了xml文件内容，代码如下：

realPath = new String(realPath.getBytes("ISO-8859-1"), "GB2312");

		filename = URLEncoder.encode(filename, "UTF-8");

		response.addHeader("Content-Disposition", "attachment;filename="

				+ new String(filename.getBytes("ISO-8859-1"), "UTF-8"));

		SAXReader reader = new SAXReader();

		Document document = null;

		try {

			document = reader.read(new File(realPath));

		} catch (DocumentException e) {

			e.printStackTrace();

		}

		response.getWriter().write(document.asXML().toString());

		System.out.println(document.asXML().toString());

但是前台没有弹窗提示选择保存路径，要怎么处理这个问题呢？各位指点一下啦！谢谢！
------解决方案--------------------

response.setContentType("application/x-msdownload");

            response.addHeader("Content-Disposition", "attachment;filename="

                + new String(filename.getBytes("ISO-8859-1"), "UTF-8"));

            InputStream inputStream = new FileInputStream(new File(realPath));

            OutputStream outputStream = response.getOutputStream();

            byte[] buffer = new byte[1024];

            int i;

            while ((i = inputStream.read(buffer)) != -1) {

                len += i;

                outputStream.write(buffer, 0, i);

                outputStream.flush();

            }

            response.setContentLength(len);

            outputStream.close();

            inputStream.close();