使用fileupload进行文件上传

// 上传路径
		SimpleDateFormat dateformat = new SimpleDateFormat("yyyy/MM/dd/HH");
		String pathdir = "/newsimages/uploadfile/"
				+ dateformat.format(new Date());//
		
		ServletContext realpathdir = request.getSession().getServletContext();
		String path = realpathdir.getRealPath(pathdir);
		// System.out.println(realpathdir);
		// 如目录不存在,创建一个
		File savedir = new File(path);
		if (!savedir.exists())
		{
			savedir.mkdirs();
		}

		// 创建一个工厂类
		DiskFileItemFactory factory = new DiskFileItemFactory();

		factory.setRepository(savedir);

		factory.setSizeThreshold(1024 * 1024);

		ServletFileUpload fileuplod = new ServletFileUpload(factory);
		
		int id = 0;
		 String fieldValue = "";
		 String filename = "";
		try
		{
			// 解析各个表单域
			List<FileItem> list = fileuplod.parseRequest(request);
			for (FileItem fileItem : list)
			{
				if (fileItem.isFormField())
				{
					// 获得简单域的名字
					String fieldName = fileItem.getFieldName();
					
			
					// 获得简单域的值
					fieldValue = fileItem.getString("UTF-8");
					
					id = Integer.parseInt(fieldValue);
					
					request.setAttribute(fieldName, fieldValue);
				}
				else
				{
					//获得file域的名字   
	                String fieldName = fileItem.getFieldName();   
	                //获得file域的值，带路径，即是路径+文件名   
	                String value = fileItem.getName();   
	                //取的file域的值的名字，不带路径   
	                int pos = value.lastIndexOf("\\");   
	                fieldValue = value.substring(pos+1);   
	                //获得是file文件的内容，而不是路径+文件名   
	                request.setAttribute(fieldName, fieldValue);
	                String ext = fieldValue.substring(fieldValue.length()-3).toLowerCase();
	                filename = UUID.randomUUID().toString()+ "."+ext;
	                //上传
	                fileItem.write(new File(savedir, filename));   
	                
				}
				
				News news = newsService.getNewsById(id);
				
				
				news.setFile("/omservice"+pathdir+"/"+ filename);
				
				
				
				news.setIsFocus(true);
				news.setIsFirst(false);
				newsService.saveNews(news);
				
				//上传文件的路径///
				request.setAttribute("imagepath", news.getFile());
}
			
			
		}
		catch(Exception e)
		{
			request.setAttribute("error", "上传失败!");
			e.printStackTrace();
		}
	
		request.setAttribute("message", "上传成功!");
		return mapping.findForward("success");