以编程方式检查JDBC中的开放连接 [英] programmatically checking for open connection in JDBC

问题描述

如何在oracle数据库的jdbc中检查打开的连接？

How do I check for an open connection in jdbc for oracle database?

注意： conn.isClosed（）不能用于此。

推荐答案

通常连接池也会使用Connection.isClosed（）方法检查是否连接仍然有效。问题是并非所有JDBC驱动程序都能正确处理此调用。所以我假设有一些简单的检查语句就像RealHowTo所说的那样。对于Oracle，他已经提到了SELECT 1 FROM Dual，它应该始终为Oracle数据库成功。我认为对不同的数据库有类似的查询。我记得在之前的项目中我们还实现了一个自己的连接池，它使用了这样的验证查询。

Usually a Connection Pool will also use the Connection.isClosed() method to check if the Connection is still valid. The problem is that not all JDBC drivers will handle this call correctly. So I assume that there are some simple check statements just like RealHowTo said. For Oracle he already mentioned the "SELECT 1 FROM Dual" which should succeed always for Oracle databases. I think that there are similar queries for the different database. I can remember that in a previous project we also implemented an own Connection Pool which used such validation queries.

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