本人在学习李腾飞的CMS视频,在进行文章附件上传时遇到了问题:
- Java code
public void add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 获取参数值 Article article = new Article(); try { article = (Article) RequestUtil.copyParams(Article.class, request); } catch (InvocationTargetException e) { // TODO Auto-generated catch block e.printStackTrace(); } // 从request中获得上传文件的有关信息 Attachment[] attachments = (Attachment[]) request.getParameterMap().get("attachs"); if (attachments != null) { for (Attachment atta : attachments) { System.out.println((atta).getName() + ",已经被上传,文件类型是:" + (atta).getContentType()); } } article.setCreatetime(new Date()); articleDao.addArticle(article); request.getRequestDispatcher("add_article_success.jsp").forward(request, response); }
下面这一句给出的错误提示是:不能进行类型转换 Cannot cast from String[] to Attachment[]
- Java code
Attachment[] attachments = (Attachment[]) request.getParameterMap().get("attachs");
因为我都是按照视频上讲的一步一操作的,我实在不知道哪里出了问题
请各位给指点一下
------解决方案--------------------------------------------------------
打印request.getParameterMap().get("attachs");来看是什么
------解决方案--------------------------------------------------------
request.getParameterMap().get("attachs");获得的是Object类型的数据,你要强转成数组类型当然会报错啊。。
------解决方案--------------------------------------------------------
用spring mvc 或者struts 框架上传文件。 很简单呀。
------解决方案--------------------------------------------------------
request.getParameterMap().get("attachs");
你前台给的数据map中名为attachs的值不是Attachment数组,而是String数组,当然转不了啦