//将装载驱动的方法封装起来，提高代码可用性
    public static Connection getConnection() {
        Connection connection = null;
        try {
            Class.forName("oracle.jdbc.OracleDriver");
            connection = DriverManager.getConnection(
                    "jdbc:oracle:thin:@localhost:1521:XE", "frank", "frank");
	//getconnection方法的三个参数分别对应url,数据库用户名，数据库密码
        } catch (Exception e) {
            e.printStackTrace();
        }
        return connection;
    }

	//将关闭数据库连接的方法封装起来，以便复用
    public static void close(ResultSet resultSet, Statement statement, Connection connection) {
	//分别对三个对象做判断，非空时进行关闭的操作
        if (resultSet != null) {
            try {
                resultSet.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        if (statement != null) {
            try {
                statement.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        if (connection != null) {
            try {
                connection.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

	//对于只有两个对象的情况单独操作，将ResultSet对象手动赋予空值，
	//调用上面的同名close方法
    public static void close(Statement statement, Connection connection) {
        close(null, statement, connection);
    }