db.java

火车票的订购系统,实现简单的查阅,定购等功能

package trainticket;

import java.sql.*;
import javax.swing.JOptionPane;

/**
 * <p>Title: </p>
 *
 * <p>Description: </p>
 *
 * <p>Copyright: Copyright (c) 2007</p>
 *
 * <p>Company: </p>
 *
 * @author not attributable
 * @version 1.0
 */
public class DB {

    Frame1 frm = new Frame1();
    public DB(Frame1 frm) {
        this.frm = frm;
    }

//得到连接
    public Connection getcon() {
        Connection con = null;
        String url = null;
        try {
            Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
            url = "jdbc:odbc:netbar";
            con = DriverManager.getConnection(url);
        } catch (SQLException ex) {
            ex.printStackTrace();
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        return con;
    }

//关闭连接
    public void close(Connection con) {
        try {
            con.close();
        } catch (SQLException ex) {
            ex.printStackTrace();
        }
    }

//查找车次,一系列判断
    public boolean find(TicketBean tb) {

        Connection con = this.getcon();
        //判断数据库是否连接
        if (con == null) {
            JOptionPane.showMessageDialog(frm, "数据库连接失败");
            return false;
        }
        //是否输入车次
        if (frm.TrainNum.getText() == null ||
            frm.TrainNum.getText().length() <= 0) {
            JOptionPane.showMessageDialog(frm, "请输入车次");
            return false;
        }
        //是否选择乘车方式
        if (frm.RaidaoHard.isSelected() == false && frm.RadioSoft.isSelected() == false) {
            JOptionPane.showMessageDialog(frm, "请选择乘车方式");
            return false;
        }
        //是否填写购买数量
        if (frm.OrderNum.getText() == null ||
            frm.OrderNum.getText().length() <= 0) {
            JOptionPane.showMessageDialog(frm, "请填写购买数量");
            return false;
        }
        //数据库结果集里rs.*只能被调用一次，所以为了多次调用而把rs.*依次赋给相同类型的变量
        try {
            float price = 0;
            int snum = 0;
            int bnum = 0;
            PreparedStatement s = con.prepareStatement(
                    "select * from Train where TrainNo = ? ");
            s.setString(1, tb.getTrainNo());
            ResultSet rs = s.executeQuery();
            if (rs.next()) {
                if (rs.getString("TrainNo").trim().equals(tb.getTrainNo())) {
                    if (frm.RaidaoHard.isSelected()) {
                        snum = rs.getInt("SeatNum");
                        tb.setSeatNum(Integer.parseInt(frm.OrderNum.getText()));
                        if (snum <= 0 ||
                            tb.getSeatNum() > snum) {
                            JOptionPane.showMessageDialog(frm, "订购失败：车票数量不足");
                            return false;
                        }
                        tb.setSeatPrice(rs.getFloat("seatPrice"));
                        price = tb.getSeatPrice() *
                                tb.getSeatNum();
                        JOptionPane.showMessageDialog(frm,
                                "车票订购成功,请支付" +
                                price + "元");
                        return true;
                    }
                    if (frm.RadioSoft.isSelected()) {
                        tb.setBedNum(Integer.parseInt(frm.OrderNum.getText()));
                        bnum =rs.getInt("bedNum");
                        if ( bnum == 0 ||
                                        tb.getBedNum() > bnum) {
                            JOptionPane.showMessageDialog(frm, "订购失败：车票数量不足");
                            return false;
                        }
                        tb.setBedPrice(rs.getFloat("bedPrice"));
                        price = tb.getBedPrice() *
                                tb.getBedNum();
                        JOptionPane.showMessageDialog(frm,
                                "车票订购成功,请支付" +
                                price
                                + "元");
                        return true;
                    }

                } else {
                    JOptionPane.showMessageDialog(frm, "无此车次");
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
        this.close(con);
        return false;

    }

public void update(TicketBean tb){
    Connection con = this.getcon();
    try {
        if(frm.RaidaoHard.isSelected()){
            tb.setSeatNum(Integer.parseInt(frm.OrderNum.getText()));
            PreparedStatement sseat = con.prepareStatement(
                    "update Train set seatNum = seatNum - ? where TrainNo =?");
            sseat.setInt(1, tb.getSeatNum());
            sseat.setString(2, tb.getTrainNo());
            sseat.executeUpdate();
            tb.setSeatNum(Integer.parseInt(frm.OrderNum.getText()));
        }
        if(frm.RadioSoft.isSelected()){
       PreparedStatement bseat = con.prepareStatement(
               "update Train set bedNum = bedNum - ? where TrainNo =?");
       bseat.setInt(1,tb.getBedNum());
       bseat.setString(2,tb.getTrainNo());
       bseat.executeUpdate();
        }
    } catch (SQLException ex) {
    }
}


}