Question

我正在编写一个简单的REST服务，它通过JDBC连接到Oracle DB。我有一个名为DatabaseRepository的类。这个类是一个单例，我在创建对象时打开与数据库的连接并始终保持活动状态。在这个类中，还有一些方法可以从数据库中检索数据并将结果解析为对象。

我现在的问题是，如果我做的是好的做法。我的思维过程是，保持永久连接（每3秒访问一次）更好，而不是为每个呼叫创建一个新连接。

代码示例：

private static DatabaseRepository instance = null;
private Connection connection = null;

private DatabaseRepository() throws ClassNotFoundException, SQLException {

    Class.forName(DRIVER_STRING);
    connection = DriverManager.getConnection(CONNECTION_STRING, USERNAME, PASSWORD);

    // Add a shutdown hook, so the connection is closed when the applications stops
    Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
        @Override
        public void run() {

            try {

                if (connection != null) {
                    connection.close();
                }

            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }));
}

public static DatabaseRepository getInstance() throws ClassNotFoundException, SQLException {

    if (instance == null) {
        instance = new DatabaseRepository();
    }

    return instance;
}

public Entity getEntity(long entityId) throws SQLException {

    if (entityId <= 0) {
        throw new IllegalArgumentException("Entity id must be greater than 0!");
    }

    PreparedStatement statement = connection.prepareStatement("SELECT * FROM tbl_entity WHERE entity_id = ?");
    statement.setLong(1, entityId);
    ResultSet resultSet = statement.executeQuery();

    // If no data was found, return null
    if (!resultSet.next()) {
        return null;
    }

    // Parse the values from the result set
    Entity entity = resultSet. ...

    statement.close();
    resultSet.close();

    return entity;
}

JDBC存储库为单例

0 个答案: