bankaccount.java

用jsp＋servlet

/**
 * A bank account has a balance that can be changed by deposits and withdrawals.
 */
import java.io.*;
public class BankAccount implements Serializable{
	/**
	 * Constructs a bank account with a zero balance.
	 */
	private int aNumber, pin;

	public BankAccount(int aNumber, int pin) {
		this.aNumber = aNumber;
		this.pin = pin;
		DBConnection db = new DBConnection();
		db.executeQuery("select * from atm where accountnumber=" + aNumber
				+ " and pin=" + pin);
		if (db.rs_next()) {
			balance = db.rs_getDouble("balanceamount");
		} else {
			balance = 0;
		}
	}

	/**
	 * Constructs a bank account with a given balance.
	 * 
	 * @param initialBalance
	 *            the initial balance
	 */
	public BankAccount(double initialBalance) {
		balance = initialBalance;
	}

	/**
	 * Withdraws money from the account.
	 * 
	 * @param the
	 *            amount of money to withdraw
	 */
	public void deposit(double amount) {
		balance = balance + amount;
		DBConnection db = new DBConnection();
		db.execute("update atm set balanceamount=" + balance
				+ "where accountnumber=" + aNumber + " and pin=" + pin);
	}

	/**
	 * Deposits money into the account.
	 * 
	 * @param the
	 *            amount of money to deposit
	 */
	public void withdraw(double amount) {
		balance = balance - amount;
		DBConnection db = new DBConnection();
		db.execute("update atm set balanceamount=" + balance
				+ "where accountnumber=" + aNumber + " and pin=" + pin);
	}

	/**
	 * Gets the account balance.
	 * 
	 * @return the account balance
	 */
	public double getBalance() {
		return balance;
	}

	private double balance;
}