java中ATM与数据库Mysql的连接

import java.sql.*;  

import java.util.*;  

public class ATM1 {  

    String code;  

    int pass;  

    double money;  

    int i=1;  

    //检查登录  

    public void checkLogin(){  

        int i=1;  

        while(i<=3){  

            System.out.print(“请输入您的卡号：”);  

            Scanner sc=new Scanner(System.in);  

            String code_=sc.nextLine();  

            System.out.print(“请输入您的密码：”);  

            int pass_=sc.nextInt();  

            try{  

                //加载驱动  

                Class.forName(“com.mysql.jdbc.Driver”);  

                //建立连接  

                java.sql.Connection conn = DriverManager.getConnection(“jdbc:mysql://localhost:3306/atmdb”,“root”,“root”);     

                //创建sql传送对象  

                Statement stmt = conn.createStatement();  

                //将sql语句通过sql传送对象传送到数据库并执行，返还结果集  

                String sql = “select * from account where code='”+code_+“‘and pass=”+pass_;  

                ResultSet rs = stmt.executeQuery(sql);    

                //当账号、密码与sql中的账号与密码相对应的时候  

                //把sql中的相关数据传送到目前变量以便进行数据操作  

                if(rs.next()){  

                    code = rs.getString(1);  

                    pass = rs.getInt(2);  

                    money = rs.getDouble(3);  

                    loadSys();  

                }  

                rs.close();  

                stmt.close();  

                conn.close();  

            }  

            //捕获异常  

            catch (Exception e){  

                System.out.println(e);  

            }  

            //出现三次错误之后提示  

            i++;  

            if( i == 3){  

            System.out.print(“您已经输错三次密码，该卡已经被锁，请及时到相关网点咨询！”);  

            }  

        }  

    }  

    //保存数据  

    //注意;下面的关键字(    “pass、code、money”)要与数据库中的名字一样，避免出现错误  

    public void saveDb(){  

        try{  

            Class.forName(“com.mysql.jdbc.Driver”);  

            java.sql.Connection conn = DriverManager.getConnection(“jdbc:mysql://localhost:3306/atmdb”,“root”,“root”);     

            Statement stmt = conn.createStatement();  

            String sql=“update account set pass =”+pass+” where code='”+code+“‘”;    

            //dode为String型，所以要用‘’括起来  

            String sql1=“update account set money=”+money+” where code='”+code+“‘”;  

            stmt.executeUpdate(sql);    //update操作进行数据更新  

            stmt.executeUpdate(sql1);  

            stmt.close();  

            conn.close();  

        }     

        catch (Exception e){  

                System.out.println(e);  

            }  

    }  

    //欢迎界面  

    public static void welcome(){  

        System.out.println(“!*****************************************!”);  

        System.out.println(“!*************欢迎使用华夏银行*************!”);  

        System.out.println(“!*****************************************!”);  

    }  

    //系统主界面  

    public void loadSys(){  

        System.out.println(“.————————————.”);  

        System.out.println(“1 查询余额                      存款 2”);  

        System.out.println(“3 取款                      修改密码 4”);  

        System.out.println(“5 退出                                “);  

        System.out.println(“.————————————.”);  

        System.out.print(“请输入相应的功能选项数字：”);  

        Scanner sz=new Scanner(System.in);  

        int num=sz.nextInt();         

        switch(num){  

            case 1:     

                chaxun();  

                break;  

            case 2:     

               cunkuan();  

               break;  

            case 3:     

               qukuan();  

               break;  

            case 4:     

               xiugai();  

               break;  

            case 5:     

               quit();  

               break;  

            default:  

               System.out.println(“您输入的数字有误！”);  

               loadSys();  

        }  

    }  

    //查询余额  

    public void chaxun(){  

        System.out.println(“您卡上的余额为：” +money);  

        loadSys();  

    }  

    //存款  

    public void cunkuan(){  

        System.out.print(“请输入存款金额：”);  

        Scanner ck=new Scanner(System.in);  

        double money1=ck.nextDouble();  

        money=money+money1;  

        saveDb();  

        System.out.println(“您卡上的余额为：” +money);  

        System.out.println(“请收好您的卡!”);  

        loadSys();  

    }  

    //取款  

    public void qukuan(){  

        System.out.print(“请输入取款金额：”);  

        Scanner qk=new Scanner(System.in);  

        double money2=qk.nextDouble();  

        if(money2>money){  

            System.out.println(“您的余额不足！”);    

            qukuan();  

        }else{  

            money=money-money2;  

            saveDb();  

            System.out.println(“您卡上的余额为：” +money);  

            System.out.println(“请收好您的现金！”);   

            loadSys();  

        }  

    }  

    //修改密码  

    public void xiugai(){  

        int cs = 0;  

        System.out.print(“请输入原密码：”);   

        Scanner mm=new Scanner(System.in);  

        int pass1=mm.nextInt();  

        System.out.print(“请输入新密码：”);   

        int pass2=mm.nextInt();  

        System.out.print(“请再次输入新密码：”);   

        int pass3=mm.nextInt();  

        if(pass==pass1&& pass2==pass3){  

            System.out.println(“修改密码成功！”);   

            pass=pass2;  

            saveDb();  

            loadSys();  

        }else{  

            if(cs<2){  

               System.out.print(“您输入的密码有误！”);   

               cs++;  

               xiugai();  

            }else{  

               quit();  

            }  

        }  

    }  

    //退出  

    public void quit(){  

        System.exit(1);       

    }  

    //主函数  

    public static void main(String args[]){  

        /*try{ 

            Class.forName(“com.mysql.jdbc.Driver”); 

            java.sql.Connection conn = DriverManager.getConnection( “jdbc:mysql://localhost:3306/atmdb”,”root”,”root”); 

            Statement stmt = conn.createStatement(); 

            String sql = “select * from account”; 

            ResultSet rs = stmt.executeQuery(sql); 

            while (rs.next()){ 

                String code = rs.getString(1); 

                int pass = rs.getInt(2); 

                double money = rs.getDouble(3); 

                System.out.println(code+”|”+pass+”|”+money); 

            } 

            rs.close(); 

            stmt.close(); 

            conn.close(); 

        } 

        catch(Exception e){ 

        System.out.println(e); 

        }*/  

        ATM1 atm = new ATM1();  

        atm.welcome();  

        atm.checkLogin();  

        }     

}