网上定餐系统网上定餐系统

package com.restrant.dao; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import java.util.List; import com.restrant.model.*; import com.restrant.dbutil.*; public class ItemsDAO { /** * 获得所有菜品信息 * * @return */ public List<ItemsBean> getItems() { Connection con = null; PreparedStatement pstmt = null; ResultSet rs = null; List<ItemsBean> list = new ArrayList<ItemsBean>(); try { con = DBUtil.getCon(); pstmt = con.prepareStatement("select * from items"); rs = pstmt.executeQuery(); while (rs.next()) { ItemsBean items = new ItemsBean(); items.setIid(rs.getInt("iid")); items.setIname(rs.getString("iname")); items.setItype(rs.getString("itype")); items.setIstock(rs.getString("istock")); items.setPrice(rs.getDouble("price")); items.setRemark(rs.getString("remark")); items.setImg(rs.getString("img")); items.setState(rs.getString("state")); list.add(items); } } catch (Exception e) { e.printStackTrace(); } finally { DBUtil.closeCon(rs, pstmt, con); } return list; } /** * 获得获得所有菜品记录数目 * * @return int */ public int getRowNumber() { Connection con = null; PreparedStatement pstmt = null; ResultSet rs = null; int num = 0; try { // 通过数据库连接类DBUtil获得数据库连接对象 con = DBUtil.getCon(); // 构建查询语句 String sql = "select count(*) as rowNumbers from items"; // 通过数据库连接类获得预编译上下文对象 pstmt = con.prepareStatement(sql); // 执行数据库查询 rs = pstmt.executeQuery(); if (rs.next()) { num = rs.getInt("rowNumbers"); } } catch (Exception ex) { ex.printStackTrace(); } finally { // 通过数据库连接类关闭数据库连接 DBUtil.closeCon(rs, pstmt, con); } return num; } /** * 根据指定的页面大小，获得页面总数 * * @param pageSize * int * @return int */ public int getTotalPage(int pageSize) { int totalPage = 1; // 临时变量，用于判断能否整除 int tempPage = 0; int rowNum = getRowNumber(); tempPage = rowNum % pageSize; if (tempPage == 0) { totalPage = rowNum / pageSize; } else { totalPage = (int) (Math.floor(rowNum / pageSize) + 1); } if (totalPage == 0) { totalPage = 1; } return totalPage; } /** * 根据指定的页面大小，获得指定页的记录 * * @param pageSize * int * @param currentPage * int * @return ArrayList */ public List<ItemsBean> getPageSet(int pageSize, int currentPage) { ArrayList list = null; Connection con = null; PreparedStatement pstmt = null; ResultSet rs = null; try { con = DBUtil.getCon(); String sql = "select top " + pageSize + " * from items where iid not in (select top " + ((currentPage - 1) * pageSize) + " iid from items)"; pstmt = con.prepareStatement(sql); rs = pstmt.executeQuery(); list = new ArrayList<ItemsBean>(); while (rs.next()) { ItemsBean items = new ItemsBean(); items.setIid(rs.getInt("iid")); items.setIname(rs.getString("iname")); items.setItype(rs.getString("itype")); items.setIstock(rs.getString("istock")); items.setPrice(rs.getDouble("price")); items.setRemark(rs.getString("remark")); items.setImg(rs.getString("img")); items.setState(rs.getString("state")); list.add(items); } } catch (Exception ex) { ex.printStackTrace(); } finally { DBUtil.closeCon(rs, pstmt, con); } return list; } }