Java模拟银行转账(操作事务)

第一步：建立一张银行账户表 叫 BankAccount 并建立一个序列id number pk //用户id
ano varchar2(30) uk //用户卡号
apassword varchar2(30) //用户密码
aname varchar2(30) //用户名
amoney number //余额

//创建银行用户表
drop table bank_account;
create table    bank_account(
id    number  constraint   bank_account_id_pk   primary key,
ano  varchar(30) constraint bank_account_ano_uk  unique,
apassword  varchar(30),
aname   varchar(30),
amoney  number
);
drop sequence bank_account_id_seq;
create sequence    bank_account_id_seq;
6.2 写一个java程序  用来开户   只要输入 账号                  密码     开户人的姓名   余额
开户信息如下                           6225880111887788     123456   zhangsan       99999999
                          6225880111887799     123456   lisi    9

第二步：创建Bean包，编写实体类public class BankAccount {
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getAno() {
return ano;
}
public void setAno(String ano) {
this.ano = ano;
}
public String getAname() {
return aname;
}
public void setAname(String aname) {
this.aname = aname;
}
public String getApassword() {
r
4000
eturn apassword;
}
public void setApassword(String apassword) {
this.apassword = apassword;
}
public String getAmoney() {
return amoney;
}
public void setAmoney(String amoney) {
this.amoney = amoney;
}
@Override
public String toString() {
return "BankAccount [id=" + id + ", ano=" + ano + ", aname=" + aname + ", apassword=" + apassword + ", amoney="
+ amoney + "]";
}
public BankAccount(String ano, String aname, String apassword, String amoney) {
super();
this.ano = ano;
this.aname = aname;
this.apassword = apassword;
this.amoney = amoney;
}
public BankAccount(int id, String ano, String aname, String apassword, String amoney) {
super();
this.id = id;
this.ano = ano;
this.aname = aname;
this.apassword = apassword;
this.amoney = amoney;
}
public BankAccount() {
super();
// TODO Auto-generated constructor stub
}
private int id;
private String ano;
private String aname;
private String apassword;
private String amoney;
}第三步：创建账号，编写开户程序import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.Scanner;
import com.xdl.util.JdbcUtil2;

public class CreateBankAccount {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.println("请输入开户的卡号:");
String ano = sc.nextLine();
System.out.println("请输入开户的名字:");
String aname = sc.nextLine();
System.out.println("请输入开户的密码:");
String apassword = sc.nextLine();
System.out.println("请输入开户的钱数:");
String smoney = sc.nextLine();
//double amoney = Double.parseDouble(smoney);
// 把输入的数据 包装成对象
BankAccount ba = new BankAccount(ano, aname, apassword, smoney);
Connection conn = null;
PreparedStatement ps = null;
conn = JdbcUtil2.getConnection();
String sql="insert into bank_account values(bank_account_id_seq.nextval,?,?,?,?)";
try {
ps = conn.prepareStatement(sql);
ps.setString(1, ba.getAno());
ps.setString(2, ba.getApassword());
ps.setString(3, ba.getAname());
ps.setDouble(4, Double.parseDouble(ba.getAmoney()));
int rows = ps.executeUpdate();
if(rows == 1) {
System.out.println("开户成功");
}else{
System.out.println("开户失败");
}
} catch (SQLException e) {
e.printStackTrace();
}finally{
JdbcUtil2.releaseResource(conn, ps, null);
}
}
}第四步：编写转账程序
1、先登录，登录成功才可以执行转账程序
2、转账逻辑时，链接会自动进行数据的提交，这样万一转入的账户不成功，则无法回退之前的操作，为了解决 操作语句 需要同时成功或同事失败 则需要关闭连接的自动提交
禁止自动提交 conn.setAutoCommit(false);
语句都成功 就提交 conn.commit() ；否则进行回滚 conn.rollback();
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Scanner;
import com.xdl.util.JdbcUtil2;

public class BankAccountTransfer {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入登录的卡号:");
        String  ano  = sc.nextLine();
        System.out.println("请输入登录的密码:");
        String  apassword = sc.nextLine();
        Connection  conn = null;
        PreparedStatement ps = null;
        /* 定义两个转账的  PreparedStatement */
        PreparedStatement from = null;
        PreparedStatement to = null;
        ResultSet  rs = null;
        BankAccount  ba = null;
        conn = JdbcUtil2.getConnection();
        String  sql="select * from bank_account where ano=? and apassword=?";
        try {
            ps=conn.prepareStatement(sql);
            ps.setString(1, ano);
            ps.setString(2, apassword);
            rs = ps.executeQuery();
            if(rs.next()){
                ba = new BankAccount(rs.getInt("id"),
                   rs.getString("ano"), rs.getString("aname"), rs.getString("apassword"),
                   rs.getString("amoney"));
            }
            if(ba!=null){
                System.out.println("登录成功");
                // 从当前账户中扣除输入的金额
                System.out.println("请输入转账的金额:");
                String  smoney=sc.nextLine();
                double  money = Double.parseDouble(smoney);
                sql="update  bank_account set amoney=amoney-? where ano=?";
                // 禁止自动提交  
                conn.setAutoCommit(false);
                from = conn.prepareStatement(sql);
                from.setDouble(1, money);
                from.setString(2, ba.getAno());
                int  fromf=from.executeUpdate();
                // 提示用户输入转入的账号  和  账户名
                System.out.println("请输入收款的账号:");
                String  toano = sc.nextLine();
                System.out.println("请输入收款人姓名:");
                String  toaname= sc.nextLine();
                sql="update  bank_account set amoney=amoney+? where ano=? and aname=?";
                to=conn.prepareStatement(sql);
                to.setDouble(1, money);
                to.setString(2, toano);
                to.setString(3, toaname);
                int tof = to.executeUpdate();
                if(fromf==1 && tof==1){
                    System.out.println("转账成功");
                    conn.commit(); //提交
                }else{
                    System.out.println("转账失败");
                    conn.rollback(); //回滚
                }
            }else{
                System.out.println("登录失败");
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            try {
                conn.rollback();
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
            e.printStackTrace();
        }finally{
            JdbcUtil2.releaseResource(conn, ps, rs);
            JdbcUtil2.releaseResource(conn, from, null);
            JdbcUtil2.releaseResource(conn, to, null);
        }
    }
}