使用java和mysql编写银行管理系统的代码

由于银行管理系统是一个比较复杂的系统，代码量比较大，这里我提供一个简单的代码示例，仅供参考：

1. Customer实体类

public class Customer {
    private int id;
    private String name;
    private String address;
    private String phone;
    
    public Customer(int id, String name, String address, String phone) {
        this.id = id;
        this.name = name;
        this.address = address;
        this.phone = phone;
    }
    
    // getters and setters
}

2. CustomerDAO类

public class CustomerDAO {
    private Connection conn;
    
    public CustomerDAO(Connection conn) {
        this.conn = conn;
    }
    
    public void addCustomer(Customer customer) throws SQLException {
        PreparedStatement ps = conn.prepareStatement("INSERT INTO customer (id, name, address, phone) VALUES (?, ?, ?, ?)");
        ps.setInt(1, customer.getId());
        ps.setString(2, customer.getName());
        ps.setString(3, customer.getAddress());
        ps.setString(4, customer.getPhone());
        ps.executeUpdate();
    }
    
    public void deleteCustomer(int id) throws SQLException {
        PreparedStatement ps = conn.prepareStatement("DELETE FROM customer WHERE id = ?");
        ps.setInt(1, id);
        ps.executeUpdate();
    }
    
    public void updateCustomer(Customer customer) throws SQLException {
        PreparedStatement ps = conn.prepareStatement("UPDATE customer SET name = ?, address = ?, phone = ? WHERE id = ?");
        ps.setString(1, customer.getName());
        ps.setString(2, customer.getAddress());
        ps.setString(3, customer.getPhone());
        ps.setInt(4, customer.getId());
        ps.executeUpdate();
    }
    
    public Customer getCustomerById(int id) throws SQLException {
        PreparedStatement ps = conn.prepareStatement("SELECT * FROM customer WHERE id = ?");
        ps.setInt(1, id);
        ResultSet rs = ps.executeQuery();
        if (rs.next()) {
            return new Customer(rs.getInt("id"), rs.getString("name"), rs.getString("address"), rs.getString("phone"));
        } else {
            return null;
        }
    }
}

3. CustomerService类

public class CustomerService {
    private CustomerDAO customerDAO;
    
    public CustomerService(CustomerDAO customerDAO) {
        this.customerDAO = customerDAO;
    }
    
    public void addCustomer(int id, String name, String address, String phone) throws SQLException {
        Customer customer = new Customer(id, name, address, phone);
        customerDAO.addCustomer(customer);
    }
    
    public void deleteCustomer(int id) throws SQLException {
        customerDAO.deleteCustomer(id);
    }
    
    public void updateCustomer(int id, String name, String address, String phone) throws SQLException {
        Customer customer = new Customer(id, name, address, phone);
        customerDAO.updateCustomer(customer);
    }
    
    public Customer getCustomerById(int id) throws SQLException {
        return customerDAO.getCustomerById(id);
    }
}

4. 用户界面代码

public class BankManagementSystemGUI {
    private CustomerService customerService;
    
    public BankManagementSystemGUI(CustomerService customerService) {
        this.customerService = customerService;
    }
    
    public void showCustomerForm() {
        // create and show customer form
    }
    
    public void addCustomer(int id, String name, String address, String phone) throws SQLException {
        customerService.addCustomer(id, name, address, phone);
    }
    
    public void deleteCustomer(int id) throws SQLException {
        customerService.deleteCustomer(id);
    }
    
    public void updateCustomer(int id, String name, String address, String phone) throws SQLException {
        customerService.updateCustomer(id, name, address, phone);
    }
    
    public Customer getCustomerById(int id) throws SQLException {
        return customerService.getCustomerById(id);
    }
}

以上是一个简单的银行管理系统的Java和MySQL实现的代码示例，仅供参考。实际实现中，需要根据具体需求进行更加详细的设计和实现。