我应该使用 ThreadLocal 来存储连接吗？
我对我的测试项目进行编码，并禁止在那里使用春季和冬眠。
我想从服务层管理交易。 为此，我创建了一个从池中获得连接并将其放入线路local的类。
这是字段和方法的一个示例。
private static ThreadLocal<Connection> threadLocalConnection;
private ComboPooledDataSource comboPooledDataSource ;
public boolean createConnectionIfAbsent() {
boolean isConnectionCreated = false;
try {
Connection currentConnection = threadLocalConnection.get();
if(currentConnection == null) {
Connection conn = this.comboPooledDataSource.getConnection();
conn.setAutoCommit(false);
threadLocalConnection.set(conn);
isConnectionCreated = true;
}
} catch (SQLException e) {
e.printStackTrace();
}
return isConnectionCreated;
}
该类还具有关闭的回滚方法。
这是我如何在服务层中管理连接的示例。
public BigDecimal getTotalOrdersCount() {
boolean connectionCreated = DBManager.getInstance().createConnectionIfAbsent();
BigDecimal ordersCount = BigDecimal.ZERO;
try {
ordersCount = orderDao.getRowNumber();
} catch (SQLException throwables) {
throwables.printStackTrace();
} finally {
if (connectionCreated) DBManager.getInstance().closeConnection();
}
return ordersCount;
}
Dao只是使用它来获得连接。
Connection connection = DBManager.getInstance().getConnection();
我没有找到其他方法来管理服务层的Servlet项目中的连接，您能告诉您是否还可以吗？如果没有 - 它有哪些缺点，我应该使用什么。
upd：
请注意此服务方法。让我们假设DAO中的每种方法都从池中获取连接并关闭它。 我确实知道我需要Connection.setautocommit（false）;要开始交易，但是在这种情况下该怎么办？ 当单个方法调用2 dao时。 只是放弃交易处理？
void setStatusDeclinedAndRefund() {
// sets Order status to DECLINED
// refund money to user's balance
}
I code my Test project and it is prohibited to use Spring and Hibernate there.
I wanted to manage my transactions from Service layer.
For this I have created a class that gets a Connection from the pool and puts it in the ThreadLocal.
This is an example of the fields and the method.
private static ThreadLocal<Connection> threadLocalConnection;
private ComboPooledDataSource comboPooledDataSource ;
public boolean createConnectionIfAbsent() {
boolean isConnectionCreated = false;
try {
Connection currentConnection = threadLocalConnection.get();
if(currentConnection == null) {
Connection conn = this.comboPooledDataSource.getConnection();
conn.setAutoCommit(false);
threadLocalConnection.set(conn);
isConnectionCreated = true;
}
} catch (SQLException e) {
e.printStackTrace();
}
return isConnectionCreated;
}
The class has also close, rollback methods.
Here is the example of how I manage Connections in a Service Layer.
public BigDecimal getTotalOrdersCount() {
boolean connectionCreated = DBManager.getInstance().createConnectionIfAbsent();
BigDecimal ordersCount = BigDecimal.ZERO;
try {
ordersCount = orderDao.getRowNumber();
} catch (SQLException throwables) {
throwables.printStackTrace();
} finally {
if (connectionCreated) DBManager.getInstance().closeConnection();
}
return ordersCount;
}
Dao just uses this to get the connection.
Connection connection = DBManager.getInstance().getConnection();
I found no other way to manage connections in a Servlet project from a Service layer, could you please tell if it is ok? If not - what drawbacks does it have and what should I use instead.
UPD:
Please pay attention to this Service method. Let's assume that Each method in DAO gets the Connection from a pool and closes it.
I do know that I need connection.setAutoCommit(false); to start a transaction, but what to do it in this kind of a situation?
When a single methods calls 2 DAO.
Just give up on a transaction handling?
void setStatusDeclinedAndRefund() {
// sets Order status to DECLINED
// refund money to user's balance
}
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（1）
否。
不要第二猜连接池。以标准方式使用它：建立连接，使用它，将其关闭。
对于给定线程中的每个数据库交互，无需使用相同的连接。另外，如果您将每个线程分配一个连接，您将遇到严重的生命问题，因为通常，请求处理线程比池中的连接更多。
No.
Don't second guess the connection pool. Use it in the standard way: get a connection, use it, close it.
There is no need to use the same connection for every database interaction in a given thread. Also, you'll have serious liveliness problems if you allocate each thread a connection, because typically there are way more request processing threads than there are connections in the pool.