servlet3.0上传文件

@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);
    }
}