模拟银行存取款钱java+MySQL

好的,我很乐意为您介绍如何使用Java和MySQL来实现一个简单的银行存取款系统。这个系统将包含基本的用户认证、账户余额查询、存款和取款功能。以下是一个基本的实现方案: 1. 数据库设计: 首先,我们需要创建一个MySQL数据库来存储用户信息和账户信息。可以创建两个表:users(用户表)和accounts(账户表)。 ```sql CREATE DATABASE bank_db; USE bank_db; CREATE TABLE users ( user_id INT AUTO_INCREMENT PRIMARY KEY, username VARCHAR(50) NOT NULL UNIQUE, password VARCHAR(50) NOT NULL ); CREATE TABLE accounts ( account_id INT AUTO_INCREMENT PRIMARY KEY, user_id INT, balance DECIMAL(10,2) DEFAULT 0.00, FOREIGN KEY (user_id) REFERENCES users(user_id) ); ``` 2. Java项目结构: 创建一个Java项目,包含以下类: - BankApp: 主类,包含main方法 - DatabaseConnection: 数据库连接类 - User: 用户实体类 - Account: 账户实体类 - BankService: 银行业务逻辑类 3. 主要代码实现: ```java // DatabaseConnection.java import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; public class DatabaseConnection { private static final String URL = "jdbc:mysql://localhost:3306/bank_db"; private static final String USER = "root"; private static final String PASSWORD = "password"; public static Connection getConnection() throws SQLException { return DriverManager.getConnection(URL, USER, PASSWORD); } } // User.java public class User { private int userId; private String username; private String password; // 构造方法、getter和setter方法 } // Account.java public class Account { private int accountId; private int userId; private double balance; // 构造方法、getter和setter方法 } // BankService.java import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; public class BankService { public User login(String username, String password) throws SQLException { String sql = "SELECT * FROM users WHERE username = ? AND password = ?"; try (Connection conn = DatabaseConnection.getConnection(); PreparedStatement pstmt = conn.prepareStatement(sql)) { pstmt.setString(1, username); pstmt.setString(2, password); ResultSet rs = pstmt.executeQuery(); if (rs.next()) { User user = new User(); user.setUserId(rs.getInt("user_id")); user.setUsername(rs.getString("username")); user.setPassword(rs.getString("password")); return user; } } return null; } public Account getAccountInfo(int userId) throws SQLException { String sql = "SELECT * FROM accounts WHERE user_id = ?"; try (Connection conn = DatabaseConnection.getConnection(); PreparedStatement pstmt = conn.prepareStatement(sql)) { pstmt.setInt(1, userId); ResultSet rs = pstmt.executeQuery(); if (rs.next()) { Account account = new Account(); account.setAccountId(rs.getInt("account_id")); account.setUserId(rs.getInt("user_id")); account.setBalance(rs.getDouble("balance")); return account; } } return null; } public boolean deposit(int accountId, double amount) throws SQLException { String sql = "UPDATE accounts SET balance = balance + ? WHERE account_id = ?"; try (Connection conn = DatabaseConnection.getConnection(); PreparedStatement pstmt = conn.prepareStatement(sql)) { pstmt.setDouble(1, amount); pstmt.setInt(2, accountId); int rows = pstmt.executeUpdate(); return rows > 0; } } public boolean withdraw(int accountId, double amount) throws SQLException { String sql = "UPDATE accounts SET balance = balance - ? WHERE account_id = ? AND balance >= ?"; try (Connection conn = DatabaseConnection.getConnection(); PreparedStatement pstmt = conn.prepareStatement(sql)) { pstmt.setDouble(1, amount); pstmt.setInt(2, accountId); pstmt.setDouble(3, amount); int rows = pstmt.executeUpdate(); return rows > 0; } } } // BankApp.java import java.sql.SQLException; import java.util.Scanner; public class BankApp { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); BankService service = new BankService(); System.out.println("欢迎使用银行系统"); System.out.print("请输入用户名: "); String username = scanner.nextLine(); System.out.print("请输入密码: "); String password = scanner.nextLine(); try { User user = service.login(username, password); if (user != null) { System.out.println("登录成功!"); Account account = service.getAccountInfo(user.getUserId()); if (account != null) { System.out.println("账户余额: " + account.getBalance()); System.out.print("请选择操作: 1.存款 2.取款 3.退出: "); int choice = Integer.parseInt(scanner.nextLine()); switch (choice) { case 1: System.out.print("请输入存款金额: "); double depositAmount = Double.parseDouble(scanner.nextLine()); if (service.deposit(account.getAccountId(), depositAmount)) { System.out.println("存款成功!"); } else { System.out.println("存款失败!"); } break; case 2: System.out.print("请输入取款金额: "); double withdrawAmount = Double.parseDouble(scanner.nextLine()); if (service.withdraw(account.getAccountId(), withdrawAmount)) { System.out.println("取款成功!"); } else { System.out.println("取款失败!可能余额不足"); } break; case 3: System.out.println("谢谢使用,再见!"); break; default: System.out.println("无效的选择"); } } else { System.out.println("无法获取账户信息"); } } else { System.out.println("登录失败!用户名或密码错误"); } } catch (SQLException e) { e.printStackTrace(); } scanner.close(); } } ``` 这个简单的银行系统实现了基本的用户登录、账户余额查询、存款和取款功能。在实际应用中,您可能需要添加更多的错误处理、安全措施以及功能扩展,比如转账功能、交易历史记录等。