public class ProfileDAOImpl implements ProfileDAO {
    Connection connection = null;
    PreparedStatement preparedStatement = null;

public void getConn() throws DAOException {
    try (FileReader reader = new FileReader("db.properties")) {
        Properties properties = new Properties();
        properties.load(reader);
        String user = properties.getProperty("user");
        String password = properties.getProperty("password");
        String dburl = properties.getProperty("dburl");
        String driver = properties.getProperty("driver");
        Class.forName(driver);
        if (connection == null) {
            connection = DriverManager.getConnection(dburl, user, password);
        }
    } catch (IOException e) {
        throw new DAOException("file error ",e);
    } catch (ClassNotFoundException e) {
        throw new DAOException("class error ",e);
    } catch (SQLException e) {
        throw new DAOException("conn error ",e);
    }
}
private PreparedStatement getPreparedStatement(String sql) throws DAOException{
    if(preparedStatement == null) {
        try {
            preparedStatement = connection.prepareStatement(sql);
        } catch (Exception e) {
            throw new DAOException("create ps error ",e);
        }
    } return preparedStatement;
}
public void updateProfile(Profile profile) throws DAOException {
    String sql = "UPDATE Profile SET user_name=?," +
            " nick_name=?, user_mail=?, password=? WHERE id=?";
    try {
        getPreparedStatement(sql);
        preparedStatement.setString(1, profile.getUserName());
        preparedStatement.setString(2, profile.getNickName());
        preparedStatement.setString(3, profile.getUserMail());
        preparedStatement.setString(4, profile.getPassword());
        preparedStatement.setInt(5, profile.getId());
        preparedStatement.executeUpdate();
    } catch (Exception e) {
        throw new DAOException("update error ",e);
    }
}
public void closeConnection() throws DAOException{
    try {
        if (preparedStatement != null) {
            preparedStatement.close();
        }
    } catch (Exception e) {
        throw new DAOException("Close (ps) error ",e);
    }
    try {
        if (connection != null) {
            connection.close();
        }
    } catch (Exception e) {
        throw new DAOException("Close (conn) error",e);
    }
}