更新菜单与更新桌号步骤完全一样，需要注意的是菜单名称含有中文，所以在servlet中将信息以xml形式发出时，应注意将其编码设定为gbk，如下：
<?xml version='1.0' encoding='gbk'?>
新建Menu数据实体类：
public class Menu {private int id;private int price;private int typeId;private String name;private String pic;private String remark;getters & setters .. }
在UpdateDao与UpdateDaoImpl中添加新方法getMenuList()获取菜单列表：
public interface UpdateDao {// 获得餐桌列表public List<Table> getTableList();// 获得菜单列表public List<Menu> getMenuList(); }
@Overridepublic List<Menu> getMenuList() {// jdbc连接数据库准备工作DBUtil util = new DBUtil();Connection conn = util.openConnection();// 读出所有菜品信息准备工作String sql = "select id, price, typeId, name, pic, remark from menutbl ";Statement statement = null;ResultSet rs = null;try {statement = conn.createStatement();rs = statement.executeQuery(sql);// 新建list容纳所有桌号实体类对象List<Menu> menulist = new ArrayList<Menu>(); while (rs.next()) {Menu menu = new Menu();menu.setId(rs.getInt(1));menu.setPrice(rs.getInt(2));menu.setTypeId(rs.getInt(3));menu.setName(rs.getString(4));menu.setPic(rs.getString(5));menu.setRemark(rs.getString(6));menulist.add(menu);}// 别忘了返回listreturn menulist;} catch (SQLException e) {e.printStackTrace();} finally {try {if (rs != null) {rs.close();rs = null;}if (statement != null) {statement.close();statement = null;}if (conn != null) {conn.close();conn = null;}} catch (SQLException e) {e.printStackTrace();}}return null;}
然后是专门为更新菜单服务的UpdateMenuServlet：
public class UpdateMenuServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {resp.setContentType("text/html");PrintWriter pw = new PrintWriter(resp.getOutputStream());// 获取所有菜单信息列表UpdateDao updateDao = new UpdateDaoImpl();List<Menu> menuList = updateDao.getMenuList();// 将所有信息以xml格式输出, 此处设定编码为gbk, 否则中文乱码pw.println("<?xml version='1.0' encoding='gbk'?>");pw.println("<menulist>");for (int i = 0; i < menuList.size(); i++) {Menu menu = menuList.get(i);pw.println("<menu>");pw.print("<id>");pw.print(menu.getId());pw.print("</id>");pw.print("<price>");pw.print(menu.getPrice());pw.print("</price>");pw.print("<typeId>");pw.print(menu.getTypeId());pw.print("</typeId>");pw.print("<name>");pw.print(menu.getName());pw.print("</name>");pw.print("<pic>");pw.print(menu.getPic());pw.print("</pic>");pw.print("<remark>");pw.print(menu.getRemark());pw.print("</remark>");pw.println("</menu>");}pw.println("</menulist>");pw.flush();pw.close();}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException {doGet(req, resp);}}
注册servlet：
<servlet><servlet-name>UpdateMenuServlet</servlet-name><servlet-class>com.moka.servlet.UpdateMenuServlet</servlet-class> </servlet><servlet-mapping><servlet-name>UpdateMenuServlet</servlet-name><url-pattern>/servlet/UpdateMenuServlet</url-pattern> </servlet-mapping>