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
     
       getMenuList();}
     
     
       getTableList();    // 获得菜单列表    public List

@Override    public List
      
        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
       
         menulist = new ArrayList
        
         ();             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list            return 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 {    @Override    protected 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
      
        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("
       ");        pw.println("
       
        ");                        for (int i = 0; i < menuList.size(); i++) {            Menu menu = menuList.get(i);            pw.println("
        
         ");                            pw.print("
         
          ");                    pw.print(menu.getId());                pw.print("
         ");                                pw.print("
         
          ");                    pw.print(menu.getPrice());                pw.print("
         ");                                pw.print("
         
          ");                    pw.print(menu.getTypeId());                pw.print("
         ");                                pw.print("
         
          ");                    pw.print(menu.getName());                pw.print("
         ");                                pw.print("
         
          ");                    pw.print(menu.getPic());                pw.print("
         ");                                pw.print("
         
          ");                    pw.print(menu.getRemark());                pw.print("
         ");                        pw.println("
        ");        }                pw.println("
       ");        pw.flush();        pw.close();    }    @Override    protected void doPost(HttpServletRequest req, HttpServletResponse resp)            throws ServletException, IOException {        doGet(req, resp);    }}
      

注册servlet：

         
      
       UpdateMenuServlet
          
      
       com.moka.servlet.UpdateMenuServlet
      
          
         
      
       UpdateMenuServlet
          
      
       /servlet/UpdateMenuServlet