Java中的文件上传更改文件名

java serclet中的文件上传更改文件名。如何在java servlet中重命名文件（更改文件名）。重命名并保存数据库。请帮助我。

我的文件上传代码。

public class AjaxImage extends MNServlet {
    private static URLCodec urlcodec = new URLCodec("UTF-8");
    private static final long serialVersionUID = 1L;

    protected void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        boolean isMultipart = ServletFileUpload.isMultipartContent(request);
         String id = request.getParameter(Plugin.PLUGIN_ID_VARIABLE);

        if (isMultipart) {          
            FileItemFactory factory = new DiskFileItemFactory();
            ServletFileUpload upload = new ServletFileUpload(factory);
            try {
                List<FileItem> multiparts = upload.parseRequest(request);
                for (FileItem item : multiparts) {
                    if (!item.isFormField()) {
                        String road = "";
                        try {                           
                            String name = new File(item.getName()).getName();
                            String relativeWebPath = "/image";
                            String absoluteFilePath = request.getServletContext().getRealPath(relativeWebPath);
                            item.write(new File(absoluteFilePath, FilenameUtils.getName(item.getName())));
                            request.setCharacterEncoding("UTF-8");
                            String data = "";
                            try {
                                data =urlcodec.decode(request.getParameter("data"), "UTF-8");
                            } catch (DecoderException e) {
                                e.printStackTrace();
                            }

                        } catch (Exception e) {}
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}