dao.java

java做的ATM查询系统、 仅供初学者参考！

package BankPackage;

import java.sql.*;
import BankPackage.DBUtil;
import BankPackage.Bean;
/**
 * 操作方法类
 * @author Administrator
 *
 */
public class DAO {
	private java.sql.ResultSet rs=null;
	private java.sql.PreparedStatement ps=null;
	private java.sql.Connection con=null;
	/**
	 * 利用帐号查询用户名和密码以及余额的方法
	 * @param accountno
	 * @return
	 */
	public Bean getBankInfo(String accountno) {
		DBUtil db=new DBUtil();
		Bean bean=null;
		
		
		try {
			con=db.getConnection();
			String sql="select * from BankInfo where accountno=?";
			ps=con.prepareStatement(sql);
			ps.setString(1, accountno);
			
			rs=ps.executeQuery();
			while(rs.next()) {
				bean=new Bean();
				bean.setMAccountno(rs.getString(1));
				bean.setMAccountname(rs.getString(2));
				bean.setMPassword(rs.getString(3));
				bean.setMBalance(rs.getFloat(4));
			}
			
		}
		catch(java.sql.SQLException sqle) {
			sqle.printStackTrace();
		}
		finally {
			db.close(rs, ps, con);
			
		}
		return bean;
		
	}
	
	public boolean update(String accountno,float balance) {
		DBUtil db=new DBUtil();
		Bean bean=null;
		
		
		try {
			con=db.getConnection();
			String sql="update BankInfo set balance=balance-? where accountno=?";
			ps=con.prepareStatement(sql);
			ps.setFloat(1, balance);
			ps.setString(2, accountno);
			
			int count=ps.executeUpdate();
			if(count>0) {
				return true;
			}
			
			
		}
		catch(java.sql.SQLException sqle) {
			sqle.printStackTrace();
		}
		finally {
			db.close(rs, ps, con);
			
		}
		return false;
		
		
		
	}
	
	

}