@WebServlet("/upload")  @MultipartConfig  public class UploadServlet extends HttpServlet{  @Override  protected void doPost(HttpServletRequest req, HttpServletResponse resp)          throws ServletException, IOException {          //获取文件部件part          Part part=req.getPart("file");          //获取请求信息          String name=part.getHeader("content-disposition");          //得到上传文件保存的路径          String root=req.getServletContext().getRealPath("/upload");          //得到上传文件的后缀名          String str=name.substring(name.lastIndexOf("."),name.length()-1);          //生成一个随机的文件名          String fileName=root+"\\"+UUID.randomUUID().toString()+str;          //保存文件          part.write(fileName);      }  }