1.共性問題：

    1. 菜系管理：

       如果刪除某個菜系：

           先判斷當前的菜系有沒有被菜品引用，如果有不能刪除！

          如果當前菜系沒有被菜品引用，可以刪除！

2. 菜品更新時候，圖片顯示

          存儲時候，存儲圖片的名稱;

          顯示時候， 拼接：

               相對目錄/圖片名稱

               /項目名/目錄/*.jpg

          注意：

              圖片名稱不能有特殊字符；

               圖片名稱不能太長

3. 編碼

       --à 數(shù)據(jù)庫編碼指定

   -à 程序要處理編碼

           GET/POST

        -à 指定在創(chuàng)建連接的時候，想數(shù)據(jù)庫發(fā)送sql語句采用的編碼

           jdbc:MySQL:///hotel?useUnicode=true&characterEncoding=utf8

2.前臺-餐桌dao實現(xiàn)

package com.xp.entity;import java.util.Date;public class DinnerTable {	PRivate int id;	private String tableName;	private int tableStatus;	private Date orderDate;	public int getId() {		return id;	}	public void setId(int id) {		this.id = id;	}	public String getTableName() {		return tableName;	}	public void setTableName(String tableName) {		this.tableName = tableName;	}	public int getTableStatus() {		return tableStatus;	}	public void setTableStatus(int tableStatus) {		this.tableStatus = tableStatus;	}	public Date getOrderDate() {		return orderDate;	}	public void setOrderDate(Date orderDate) {		this.orderDate = orderDate;	}	@Override	public String toString() {		return "DinnerTable [id=" + id + ", tableName=" + tableName				+ ", tableStatus=" + tableStatus + ", orderDate=" + orderDate				+ "]";	}}package com.xp.dao;import java.util.List;import com.xp.entity.DinnerTable;import com.xp.entity.TableStatus;public interface IDinnerTableDao {	/**	 * 根據(jù)預定狀態(tài)查詢	 */	List<DinnerTable> findByStatus(TableStatus ts);	/**	 * 主鍵查詢	 */	DinnerTable findById(int id);}package com.xp.entity;/** * 餐桌狀態(tài) * @author Jie.Yuan * */public enum TableStatus {	/**	 * Free   餐車處于未預定	 * PlanIn 餐車處于已預定狀態(tài)	 */	Free,PlanIn;}package com.xp.dao.impl;import java.util.List;import org.apache.commons.dbutils.handlers.BeanHandler;import org.apache.commons.dbutils.handlers.BeanListHandler;import com.xp.dao.IDinnerTableDao;import com.xp.entity.DinnerTable;import com.xp.entity.TableStatus;import com.xp.utils.JdbcUtils;public class DinnerTableDao implements IDinnerTableDao {	@Override	public DinnerTable findById(int id) {		String sql = "select * from dinnerTable where id=?";		try {			return JdbcUtils.getQuerrRunner().query(sql, new BeanHandler<DinnerTable>(DinnerTable.class), id);		} catch (Exception e) {			throw new RuntimeException(e);		}	}	@Override	public List<DinnerTable> findByStatus(TableStatus ts) {		String sql = "select * from dinnerTable where tableStatus=?";//		int status = -1;		// 判斷		//		if (ts == TableStatus.Free) {//			status = 0;   // 未預定狀態(tài)//		} else {//			status = 1;//		}//				try {			return JdbcUtils.getQuerrRunner().query(sql, new BeanListHandler<DinnerTable>(DinnerTable.class), ts.ordinal());		} catch (Exception e) {			throw new RuntimeException(e);		}	}}3.前臺-餐桌顯示完整實現(xiàn)package com.xp.service;import java.util.List;import com.xp.entity.DinnerTable;public interface IDinnerTableService {	/**	 * 查詢所有未預定的餐桌	 */	List<DinnerTable> findNoUseTable();		/**	 * 根據(jù)主鍵查詢	 */	DinnerTable findById(int id);}package com.xp.service.impl;import java.util.List;import com.xp.dao.IDinnerTableDao;import com.xp.entity.DinnerTable;import com.xp.entity.TableStatus;import com.xp.factory.BeanFactory;import com.xp.service.IDinnerTableService;public class DinnerTableService implements IDinnerTableService{	// 調用的Dao, 通常工廠創(chuàng)建實例	private IDinnerTableDao dinnerTableDao = BeanFactory.getInstance(			"dinnerTableDao", IDinnerTableDao.class);	@Override	public DinnerTable findById(int id) {		try {			return dinnerTableDao.findById(id);		} catch (Exception e) {			throw new RuntimeException(e);		}	}	@Override	public List<DinnerTable> findNoUseTable() {		try {			// 調用dao的根據(jù)狀態(tài)查詢的方法，查詢沒有預定的餐桌			return dinnerTableDao.findByStatus(TableStatus.Free);		} catch (Exception e) {			throw new RuntimeException(e);		}	}}package com.xp.utils;import java.io.IOException;import javax.servlet.RequestDispatcher;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class WebUtils {	/**	 * 跳轉的通用方法	 */	public static void goTo(HttpServletRequest request, HttpServletResponse response, Object uri)			throws ServletException, IOException {		if (uri instanceof RequestDispatcher){			((RequestDispatcher)uri).forward(request, response);		} else if (uri instanceof String) {			response.sendRedirect(request.getContextPath() + uri);		} 	}}package com.xp.entity;public class Food {	private int id;// INT PRIMARY KEY AUTO_INCREMENT, -- 主鍵	private String foodName;// VARCHAR(20), -- 菜名稱	private int foodType_id;// INT, -- 所屬菜系, 外鍵字段	private double price;// DOUBLE, -- 價格	private double mprice;// DOUBLE, -- 會員價格	private String remark;// VARCHAR(200), -- 簡介	private String img;// VARCHAR(100) -- 圖片	public int getId() {		return id;	}	public void setId(int id) {		this.id = id;	}	public String getFoodName() {		return foodName;	}	public void setFoodName(String foodName) {		this.foodName = foodName;	}	public int getFoodType_id() {		return foodType_id;	}	public void setFoodType_id(int foodTypeId) {		foodType_id = foodTypeId;	}	public double getPrice() {		return price;	}	public void setPrice(double price) {		this.price = price;	}	public double getMprice() {		return mprice;	}	public void setMprice(double mprice) {		this.mprice = mprice;	}	public String getRemark() {		return remark;	}	public void setRemark(String remark) {		this.remark = remark;	}	public String getImg() {		return img;	}	public void setImg(String img) {		this.img = img;	}}package com.xp.utils;/*** 封裝條件* * */public class Condition {	// 菜的類別作為條件	private int foodTypeId;	// 才的名稱作為條件	private String foodName;	public int getFoodTypeId() {		return foodTypeId;	}	public void setFoodTypeId(int foodTypeId) {		this.foodTypeId = foodTypeId;	}	public String getFoodName() {		return foodName;	}	public void setFoodName(String foodName) {		this.foodName = foodName;	}}package com.xp.utils;import java.util.List;/** * 封裝分頁參數(shù) */public class PageBean<T> {	// 當前頁	private int currentPage = 1;	// 每頁顯示的行數(shù)	private int pageCount = 6;	// 總記錄數(shù)	private int totalCount;	// 總頁數(shù)	private int totalPage;	// 每頁的數(shù)據(jù)	private List<T> pageData;	// 封裝所有的查詢條件	private Condition condition;	public int getTotalPage() {		// 總頁數(shù) = 總記錄 / 每頁顯示行數(shù) (+ 1)		if (totalCount % pageCount == 0) {			totalPage = totalCount / pageCount;		} else {			totalPage = totalCount / pageCount + 1;		}		return totalPage;	}	public void setTotalPage(int totalPage) {		this.totalPage = totalPage;	}	public int getCurrentPage() {		return currentPage;	}	public void setCurrentPage(int currentPage) {		this.currentPage = currentPage;	}	public int getPageCount() {		return pageCount;	}	public void setPageCount(int pageCount) {		this.pageCount = pageCount;	}	public int getTotalCount() {		return totalCount;	}	public void setTotalCount(int totalCount) {		this.totalCount = totalCount;	}	public List<T> getPageData() {		return pageData;	}	public void setPageData(List<T> pageData) {		this.pageData = pageData;	}	public Condition getCondition() {		return condition;	}	public void setCondition(Condition condition) {		this.condition = condition;	}}package com.xp.dao;import com.xp.entity.Food;import com.xp.utils.PageBean;public interface IFoodDao {	/**	 * 分頁且按條件查詢所有的菜品	 */	void getAll(PageBean<Food> pb);		/**	 * 按條件統(tǒng)計菜品的總記錄數(shù)	 */	int getTotalCount(PageBean<Food> pb);		/**	 * 根據(jù)id查詢	 */	Food findById(int id);}package com.xp.dao.impl;import java.sql.SQLException;import java.util.ArrayList;import java.util.List;import org.apache.commons.dbutils.handlers.BeanHandler;import org.apache.commons.dbutils.handlers.BeanListHandler;import org.apache.commons.dbutils.handlers.ScalarHandler;import com.xp.dao.IFoodDao;import com.xp.entity.Food;import com.xp.utils.Condition;import com.xp.utils.JdbcUtils;import com.xp.utils.PageBean;public class FoodDao implements IFoodDao {	@Override	public Food findById(int id) {		StringBuffer sb = new StringBuffer();		sb.append("select");		sb.append("		f.id,");		sb.append("		f.foodName,");		sb.append("		f.price,");		sb.append("		f.mprice,");		sb.append("		f.remark,");		sb.append("		f.img,");		sb.append("		f.foodType_id,");		sb.append("		t.typeName ");		sb.append("from ");		sb.append("		food f, ");		sb.append("		foodtype t ");		sb.append("where 1=1");		sb.append("		and f.foodType_id=t.id");		try {			return JdbcUtils.getQuerrRunner().query(sb.toString(),					new BeanHandler<Food>(Food.class));		} catch (Exception e) {			throw new RuntimeException(e);		}	}	@Override	public void getAll(PageBean<Food> pb) {		// 獲取條件對象		Condition condition = pb.getCondition();		// 條件之類別id		int typeId = condition.getFoodTypeId();		// 條件之菜品名稱		String foodName = condition.getFoodName();		StringBuffer sb = new StringBuffer();		sb.append("select");		sb.append("		f.id,");		sb.append("		f.foodName,");		sb.append("		f.price,");		sb.append("		f.mprice,");		sb.append("		f.remark,");		sb.append("		f.img,");		sb.append("		f.foodType_id,");		sb.append("		t.typeName ");		sb.append("from ");		sb.append("		food f, ");		sb.append("		foodtype t ");		sb.append("where 1=1");		sb.append("		and f.foodType_id=t.id ");		// 存儲查詢條件對應的值		List<Object> list = new ArrayList<Object>();		/******* 拼接查詢條件 *********/		// 類別id條件		if (typeId > 0) {			sb.append("	and f.foodType_id=?");			list.add(typeId); // 組裝條件值		}		// 菜品名稱		if (foodName != null && !"".equals(foodName.trim())) {			sb.append("  and f.foodName like ?");			list.add(foodName); // 組裝條件值		}		/********* 分頁條件 **********/		sb.append(" LIMIT ?,?");		/***** 判斷：當當前頁< 1， 設置當前頁為1； 當當前頁>總頁數(shù)，設置當前頁為總頁數(shù) ******/		// 先查詢總記錄數(shù)		int totalCount = getTotalCount(pb); // ?		// 設置分頁bean參數(shù)之總記錄數(shù)		pb.setTotalCount(totalCount);		if (pb.getCurrentPage() < 1) {			pb.setCurrentPage(1);		} else if (pb.getCurrentPage() > pb.getTotalPage()) {			pb.setCurrentPage(pb.getTotalPage());		}		// 起始行		int index = (pb.getCurrentPage() - 1) * pb.getPageCount();		// 返回記錄行		int count = pb.getPageCount();		list.add(index); // 組裝條件值 - 起始行		list.add(count); // 組裝條件值 - 查詢返回的行		// 按條件、分頁查詢		try {			List<Food> pageData = JdbcUtils.getQuerrRunner().query(					sb.toString(), new BeanListHandler<Food>(Food.class),					list.toArray());			// 把查詢到的數(shù)據(jù)設置到分頁對象中			pb.setPageData(pageData);		} catch (SQLException e) {			throw new RuntimeException(e);		}	}	@Override	public int getTotalCount(PageBean<Food> pb) {		// 獲取條件對象		Condition condition = pb.getCondition();		// 條件之類別id		int typeId = condition.getFoodTypeId();		// 條件之菜品名稱		String foodName = condition.getFoodName();		StringBuffer sb = new StringBuffer();		sb.append("select");		sb.append("		count(*) ");		sb.append("from ");		sb.append("		food f, ");		sb.append("		foodtype t ");		sb.append("where 1=1");		sb.append("		and f.foodType_id=t.id ");		// 存儲查詢條件對應的值		List<Object> list = new ArrayList<Object>();		/******* 拼接查詢條件 *********/		// 類別id條件		if (typeId > 0) {			sb.append("	and f.foodType_id=?");			list.add(typeId); // 組裝條件值		}		// 菜品名稱		if (foodName != null && !"".equals(foodName.trim())) {			sb.append("  and f.foodName like ?");			list.add(foodName); // 組裝條件值		}		try {			// 查詢			Long num = JdbcUtils.getQuerrRunner().query(sb.toString(),					new ScalarHandler<Long>(), list.toArray());			return num.intValue();		} catch (SQLException e) {			throw new RuntimeException(e);		}	}}package com.xp.service;import com.xp.entity.Food;import com.xp.utils.PageBean;public interface IFoodService {	/**	 * 主鍵查詢	 */	Food findById(int id);	/**	 * 分頁查詢	 */	void getAll(PageBean<Food> pb);}package com.xp.service.impl;import com.xp.dao.IFoodDao;import com.xp.entity.Food;import com.xp.factory.BeanFactory;import com.xp.service.IFoodService;import com.xp.utils.PageBean;public class FoodService implements IFoodService {	// 創(chuàng)建dao	private IFoodDao foodDao = BeanFactory.getInstance("foodDao", IFoodDao.class);		@Override	public Food findById(int id) {		try {			return foodDao.findById(id);		} catch (Exception e) {			throw new RuntimeException(e);		}	}	@Override	public void getAll(PageBean<Food> pb) {		try {			foodDao.getAll(pb);		} catch (Exception e) {			throw new RuntimeException(e);		}	}}package com.xp.servlet;import java.io.IOException;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.xp.entity.DinnerTable;public class IndexServlet extends BaseServlet {	/*	 * // 創(chuàng)建Service private IDinnerTableService dinnerTableService =	 * BeanFactory.getInstance("dinnerTableService", IDinnerTableService.class);	 * 	 * 	 * 	 * public void doGet(HttpServletRequest request, HttpServletResponse	 * response) throws ServletException, IOException {	 * 	 * // 獲取操作的類型 String method = request.getParameter("method"); if (method ==	 * null) { // 默認執(zhí)行的方法： 進入前臺列表的首頁 method = "listTable"; }	 * 	 * // 判斷 if ("listTable".equals(method)) { // 1. 前臺首頁：顯示所有未預定的餐桌	 * listTable(request,response); }	 * 	 * }	 * 	 * public void doPost(HttpServletRequest request, HttpServletResponse	 * response) throws ServletException, IOException { this.doGet(request,	 * response); }	 */	private static final long serialVersionUID = 1L;	// 1. 前臺首頁：顯示所有未預定的餐桌	public Object listTable(HttpServletRequest request,			HttpServletResponse response) throws ServletException, IOException {		// 保存跳轉資源(轉發(fā)/重定向)		Object uri = null;		// 查詢所有未預定餐桌		List<DinnerTable> list = dinnerTableService.findNoUseTable();		// 保存到request		request.setAttribute("listDinnerTable", list);		// 跳轉到首頁顯示		uri = request.getRequestDispatcher("/app/index.jsp");		return uri;		// 跳轉		// WebUtils.goTo(request, response, uri);	}}package com.xp.servlet;import java.io.IOException;import java.lang.reflect.Method;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.xp.factory.BeanFactory;import com.xp.service.IDinnerTableService;import com.xp.service.IFoodService;import com.xp.service.IFoodTypeService;import com.xp.utils.WebUtils;/** * 項目中通用的Servlet，希望所有的servlet都繼承此類 * @author Jie.Yuan */public abstract class BaseServlet extends HttpServlet {		// 創(chuàng)建Service	protected IDinnerTableService dinnerTableService = 		BeanFactory.getInstance("dinnerTableService", IDinnerTableService.class);	protected IFoodTypeService foodTypeService = 		BeanFactory.getInstance("foodTypeService",IFoodTypeService.class);	protected IFoodService foodService = 		BeanFactory.getInstance("foodService",IFoodService.class);	@Override	protected void doGet(HttpServletRequest request, HttpServletResponse response)			throws ServletException, IOException {		// (保存跳轉的資源)  方法返回值		Object returnValue = null;				// 獲取操作類型;  【約定 > 俗成： 操作類型的值，必須對應servlet中的方法名稱】		String methodName = request.getParameter("method");  // listTable				try {			// 1. 獲取當前運行類的字節(jié)碼			Class clazz = this.getClass();			// 2. 獲取當前執(zhí)行的方法的Method類型			Method method = clazz.getDeclaredMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);			// 3. 執(zhí)行方法			returnValue = method.invoke(this, request,response);		} catch (Exception e) {			e.printStackTrace();			returnValue = "/error/error.jsp";		}				// 跳轉		WebUtils.goTo(request, response, returnValue);	}		@Override	protected void doPost(HttpServletRequest req, HttpServletResponse resp)			throws ServletException, IOException {		this.doGet(req, resp);	}}package com.xp.servlet;import java.io.IOException;import java.util.List;import javax.servlet.ServletException;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.Httpsession;import com.xp.entity.DinnerTable;import com.xp.entity.Food;import com.xp.entity.FoodType;import com.xp.utils.Condition;import com.xp.utils.PageBean;public class FoodServlet extends BaseServlet {	/**	 * 1. 進入主頁，顯示菜品以及菜系	 */	public Object foodDetail(HttpServletRequest request,			HttpServletResponse response) throws ServletException, IOException {		HttpSession session = request.getSession();		// 1.1 獲取餐桌ID,根據(jù)ID查詢，再把查詢到的結果保存到session （生成訂單用）		// 只需要執(zhí)行一次即可: 先從session獲取看有沒有餐桌對象； 如果沒有，就執(zhí)行根據(jù)主鍵查詢；		// 如果sesison中已經有餐桌對象，就不執(zhí)行主鍵查詢		Object obj = session.getAttribute("dinnerTable");		// 判斷		if (obj == null) {			// 只在第一次執(zhí)行的時候，查詢餐桌對象			String tableId = request.getParameter("tableId");			DinnerTable dt = dinnerTableService.findById(Integer					.parseInt(tableId));			// 保存到session			session.setAttribute("dinnerTable", dt);		}		// 1.2 查詢所有的“菜品信息”, 保存		PageBean<Food> pb = new PageBean<Food>();		// 分頁參數(shù)： 獲取當前頁參數(shù)		String curPage = request.getParameter("currentPage");		// 判斷		if (curPage == null || "".equals(curPage.trim())) {			// 第一次訪問，設置當前頁為1			pb.setCurrentPage(1);		} else {			// 【設置當前頁參數(shù)】			pb.setCurrentPage(Integer.parseInt(curPage));		}		// 條件對象		Condition condition = new Condition();		// 分頁參數(shù)： 菜系id		String foodTypeId = request.getParameter("foodTypeId");		if (foodTypeId != null) { // 如果類別為null,不作為條件，那就查詢全部			// 設置條件			condition.setFoodTypeId(Integer.parseInt(foodTypeId));		}		// 分頁參數(shù)： 菜名稱		String foodName = request.getParameter("foodName");		// 設置菜品參數(shù)		condition.setFoodName(foodName);		// 【設置條件對象到pb中】		pb.setCondition(condition);		// ---->分頁查詢		foodService.getAll(pb);		// 保存查詢后的pb對象		request.setAttribute("pb", pb);		// 1.3 查詢所有的“菜系信息”， 保存		List<FoodType> listFoodType = foodTypeService.getAll();		request.setAttribute("listFoodType", listFoodType);		// 1.4 跳轉(轉發(fā))		return request.getRequestDispatcher("/app/caidan.jsp");	}}