java成长之路-文件下载

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //通过路径得到一个输入流
        String path = this.getServletContext().getRealPath("/WEB-INF/classes/欣欣.JPG");
        FileInputStream File =  new FileInputStream(path);
        //创建字节输出流
        ServletOutputStream sos = response.getOutputStream();
        //得到要下载的文件名
        String fileName = path.substring(path.lastIndexOf("\\")+1);
        //设置文件名的编码
        fileName = URLEncoder.encode(fileName, "UTF-8");
        
        //告知客户端要下载文件
        response.setHeader("content-disposition", "attachment;fileName-"+fileName);
        response.setHeader("content-type", "image/jpeg");
        
        //执行输出操作
        int len = 1;
        byte[] b = new byte[1024];
        while ((len=File.read(b))!=-1){
            sos.write(b,0,len);
        }
        File.close();
    }