1，html页面，上传使用input type=file控件，其所在的form必须加上enctype="multipart/form-data"
2,后台借助于两个开源包
commons-fileupload-1.2.1.jar
commons-io-1.3.2.jar
引入包之后，后台处理的代码如下
private void process(HttpServletRequest request, HttpServletResponse response) { // 进行用户更新,以及联系文件的存储 response.setCharacterEncoding("utf-8"); response.setContentType("html;charset=utf-8"); FileItemFactory factory = new DiskFileItemFactory(); ServletFileUpload upload = new ServletFileUpload(factory); upload.setHeaderEncoding(request.getCharacterEncoding()); try { List list = upload.parseRequest(request); for (int i = 0; i < list.size(); i++) { FileItem item = list.get(i); if (item.isFormField()) { // 说明是普通的表单字段 // updUser(item); // request.getRequestDispatcher("/listUser").forward(request, response); } else if(!item.getName().equals("")){ // 说明是文件 saveFile(item); } } } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } private void saveFile(FileItem item) { String fileName=item.getName(); //防止文件重名 String imageFileName = new Date().getTime() + new Random().nextInt(1000) +fileName.substring(fileName .lastIndexOf(".") ); //网站的物理跟路径 String rootPath=this.getServletContext().getRealPath("/"); System.out.println("UpdUser:rootPath:"+rootPath); String path=rootPath+"files\\"; File dir=new File(path); if(!dir.exists()){ dir.mkdirs(); } //将文件写入物理路径 try { item.write(new File(path,imageFileName)); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } }