java web开发 图片上传功能

    public String execute() throws Exception {
        //获得username
        Map session = ServletActionContext.getContext().getSession();
        String username = (String) session.get("username");
        
        //创建一个输入流
        InputStream is = new FileInputStream(myFile);
        //设置文件保存目录
        String photoPath = 
            ServletActionContext.getServletContext().getRealPath("/user/photo/" + username);
        File filePhotoPath = new File(photoPath);
        if(!filePhotoPath.isDirectory()) {
            filePhotoPath.mkdir();
        }
        
        //解决中文文件名问题
        String extension = FilenameUtils.getExtension(this.getMyFileFileName());
        String filename = UUID.randomUUID().toString() + "."+ extension;
        
        //设置目标文件
        File tofile = new File(photoPath,filename);
        //使用输出流来包装目标文件
        OutputStream os = new FileOutputStream(tofile);
        byte[] buffer = new byte[1024];
        int length = 0;
        while((length = is.read(buffer)) > 0) {
            os.write(buffer, 0, length);
        }
        //关闭输入流
        is.close();
        //关闭输出流
        os.close();
        
        return this.SUCCESS;
    }