public class MyFileRender extends Render {

    private static final String DEFAULT_FILE_CONTENT_TYPE = "application/octet-stream";
    private File file;
    private ServletContext servletContext;

    public MyFileRender(String fileName) {
        if(StrKit.isBlank(fileName)) {
            throw new IllegalArgumentException("fileName can not be blank.");
        } else {
            fileName = fileName.trim();
            String fullFileName;
            String baseDownloadPath = InternShipManagementConfig.FILE_HOST;
            if(!fileName.startsWith("/") && !fileName.startsWith("\\")) {
                fullFileName = baseDownloadPath + File.separator + fileName;
            } else if(baseDownloadPath.equals("/")) {
                fullFileName = fileName;
            } else {
                fullFileName = baseDownloadPath + fileName;
            }

            this.file = new File(fullFileName);
        }
        this.servletContext = JFinal.me().getServletContext();
    }
     
    public MyFileRender(File file) {
        this.file = file;
        this.servletContext =  JFinal.me().getServletContext();
    }
 
    @Override
    public void render() {
         
        if (file == null || !file.isFile() || file.length() > Integer.MAX_VALUE) {
            RenderFactory.me().getErrorRender(404).setContext(request, response).render();
            return ;
        }
        //源码中的代码
        //response.addHeader("Content-disposition", "attachment; filename=" + file.getName());
        //修改后的代码 解决中文乱码问题
        try {
            response.addHeader("Content-disposition", 
                "attachment; filename=" + new String(file.getName().getBytes("utf-8"), "ISO8859-1"));
        } catch (UnsupportedEncodingException e1) {
            e1.printStackTrace();
        }
        String contentType = servletContext.getMimeType(file.getName());
        if (contentType == null) {
            contentType = DEFAULT_FILE_CONTENT_TYPE;        // "application/octet-stream";
        }
         
        response.setContentType(contentType);
        response.setContentLength((int)file.length());
        InputStream inputStream = null;
        OutputStream outputStream = null;
        try {
            inputStream = new BufferedInputStream(new FileInputStream(file));
            outputStream = response.getOutputStream();
            byte[] buffer = new byte[1024];
            for (int n = -1; (n = inputStream.read(buffer)) != -1;) {
                outputStream.write(buffer, 0, n);
            }
            outputStream.flush();
        }
        catch (Exception e) {
            throw new RenderException(e);
        }
        finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}