最终处理空连接 [英] Handling a null Connection in finally
问题描述
我建立了数据库连接。然后,我尝试建立连接并在有异常的情况下返回。在代码的更下方,我有一个Final模块,我打算将其用作捕获所有连接的工具。
I establish a database connection. I then try to make the connection and return if there is an exception. Further down in the code I have a Finally block that I intend to use as a catch all to close the connection.
Connection con = null;
try{
try{
con = connectDB();
}
catch{
return;
}
...code
catch{
return;
}
finally{
con.close();
}
但是,如果初始连接失败,它将跳转到Final块, con.close()引发空指针异常。解决此问题的最佳方法是什么?有没有办法测试con是否为null?我已经尝试过if(con.isValid(0))和con.equals(null)和con == null,它们都不起作用。
However, if the initial connect fails, it jumps to the Finally block where my con.close() throws a null pointer exception. What is the best way to get around this? Is there a way to test if the con is null? I've tried if(con.isValid(0)) and con.equals(null) and con == null, none of them work.
推荐答案
连接
实现 AutoClosable
,因此您可以使用尝试使用资源语句。
Connection
implements AutoClosable
so you can use a try-with-resources statement.
try (Connection con = connectDB()) {
[some code]
}
这篇关于最终处理空连接的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!