HttpServletRequest.getSession（false）：什么时候返回null？ [英] HttpServletRequest.getSession(false): When does it return null?

问题描述

我想知道在调用 HttpServletRequest.getSession（false）

另外：是否有关于HttpSession的好教程？我想得到如下细节：何时无效（）？有什么后果？我需要检查返回的HttpSession是否有效？ ...< ==请在评论中回答。

Also: Are there good tutorials on HttpSession? I'd like to get details like: when to invalidate()? what are the consequences? do I need to check if the returned HttpSession is valid? ... <== Answer that in a comment please.

推荐答案

你几乎不应该期望一个空值。正如文档所述，如果请求没有活动会话（通常，您将在请求的过滤器链中检查该会话），则会创建会话。如果你从中得到一个空值，我会打赌底层操作系统有问题：没有足够的内存来产生一个会话会想到。

You should practically never expect a null value. As the documentation says, if there is no active session for a request (usually, you would check for that in the filter chain of a request), a session will be created. If you get a null value from this, I'd wager that there is a problem in the underlying OS: Not enough memory to spawn a session would come to mind.

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