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Some errors with my ActiveSessions counter

 
Jenkin Zheng
Greenhorn
Posts: 12
Eclipse IDE Java Opera
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Hi, everyone! I want to count active sessions on server. So I implement javax.servlet.http.HttpSessionListener, Here is a part code of SessionCounter
Here is my test the counter code:
Sometimes, the result is not right, like:[null]active sessions on server.
Why does it show null?I'm a newer!
thanks, everyone!
 
Piyush Joshi
Ranch Hand
Posts: 207
Eclipse IDE Firefox Browser jQuery
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may be because you are printing it too early..
print it after the if/else block after you set the attribute in your code..
 
syed aq
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Donot use listener, in rare cases listeners are not fired
 
Piyush Joshi
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syed aq wrote:Donot use listener, in rare cases listeners are not fired

Can you please explain what are the cases when listeners will not be fired. (except when the server crashes)
 
It is sorta covered in the JavaRanch Style Guide.
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