DAO에 대한 코드 최적화

package cn.itcast.dao.refactor;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

import cn.itcast.dao.Impl.DaoException;
import cn.itcast.jdbc.JdbcUtils;

//         
public abstract class AbstractDao {

    public int update(String sql, Object[] args) { 
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;

        try {
            conn = JdbcUtils.getConnection();
            ps = conn.prepareStatement(sql);
            for (int i = 0; i < args.length; i++) {
                ps.setObject(i + 1, args[i]);
            }
            return ps.executeUpdate();
        } catch (SQLException e) {
            throw new DaoException(e.getMessage(), e);
        } finally {
            JdbcUtils.free(rs, ps, conn);
        }
    }

    public Object find(String sql, Object[] args) {
        Connection conn = null;
        PreparedStatement ps = null;
        ResultSet rs = null;

        try {
            conn = JdbcUtils.getConnection();
            ps = conn.prepareStatement(sql);
            for (int i = 0; i < args.length; i++) {
                ps.setObject(i + 1, args[i]);
            }
            rs = ps.executeQuery();
            Object obj = null;
            while (rs.next()) { //          
                obj = rowMapper(rs);
            }
            return obj;
        } catch (SQLException e) {
            throw new DaoException(e.getMessage(), e);
        } finally {
            JdbcUtils.free(rs, ps, conn);
        }
    }

    abstract protected Object rowMapper(ResultSet rs)throws SQLException;
}

package cn.itcast.dao.refactor;

import java.sql.ResultSet;
import java.sql.SQLException;

import cn.itcast.domain.User;

public class UserDaoImpl extends AbstractDao{

    public static void main(String[] args) {

    }

    public User findUser(String loginName,String password){
        String sql="select id,name,money,birthday from user where name=?";
        Object[]args=new Object[]{loginName};
        return (User)super.find(sql, args);
    }

    protected Object rowMapper(ResultSet rs)throws SQLException{
        User user=new User();
        user.setId(rs.getInt("id"));
        user.setName(rs.getString("name"));
        user.setMoney(rs.getFloat("money"));
        user.setBirthday(rs.getDate("birthday"));
        return user;
    }

    public void update(User user) {
        String sql="update user set name=?,birthday=?,money=? where id=?";
        Object[]args=new Object[]{user.getName(),user.getBirthday(),user.getMoney(),user.getId()};
        super.update(sql, args);
    }

    public void delete(User user){  //        
        String sql="delete from user where id=?";
        Object[]args=new Object[]{user.getId()};
        super.update(sql, args);

    }
}