ファイル保存キャンセルをキャッチ

    String fileName = request.getParameter("name");

    try {
        InputStream inputStream = null;
        try {
            inputStream = new FileInputStream(file);
        } catch (FileNotFoundException e1) {
            throw new TargetFileNotFoundException(e1);
        }
        response.setContentType("application/octet-stream");
        String fileName;
        try {
            fileName = new String(file.getName().getBytes("SJIS"), "ISO8859_1");
        } catch (UnsupportedEncodingException e3) {
            fileName = "EncodingMiss" + file.getName();
        }
        response.setHeader(
                "Content-Disposition",
                "attachment; filename=" + fileName);
        // ファイルをバイトで読んで送信
        int size;
        byte[] buffer = new byte[1024];
        try {
            while ((size = inputStream.read(buffer)) != -1) {
                response.getOutputStream().write(buffer, 0, size);
                response.getOutputStream().flush();
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (Exception e2) {
                    e.printStackTrace();
                }
            }
        }
    } catch (Exception e) {
        e.printStackTrace();
    }