JAVA 下载单个文件

    public void toDownLoad(String ape505, HttpServletRequest request, HttpServletResponse response) throws IOException {

        //获取文件后缀名

        String ext = ape505.substring(ape505.lastIndexOf(".") + 1).toUpperCase();

        // 读到流中

        // 文件的存放路径

        InputStream inStream = new FileInputStream( request.getSession().getServletContext().getRealPath("/upload/本级预警处理上传目录/")+ape505);

        // 设置输出的格式

        response.reset();

        response.setContentType(ext);

        response.addHeader("Content-Disposition", "attachment; filename=\"" + ape505 + "\"");

        // 循环取出流中的数据

        byte[] b = new byte[100];

        int len;

        try {

            while ((len = inStream.read(b)) > 0) {

                response.getOutputStream().write(b, 0, len);

            }

            inStream.close();

        } catch (IOException e) {

            e.printStackTrace();

        }

    }