在原始接收线程之外访问HttpSession [英] Accessing HttpSession outside of the originally receiving thread

问题描述

我正在使用Spring3.当控制器获取请求时，它将控制权传递给Service Bean中以@Async注释的方法someMethod()，然后返回.当我在someMethod() HttpSession对象中访问时，收到此异常

I'm using Spring 3. When controller gets requests it passes control to method someMethod() annotated with @Async in Service bean and then returns. When I access in someMethod() HttpSession object I receive this exception

java.lang.IllegalStateException: No thread-bound request found: Are you 
referring to request attributes outside of an actual web request, or 
processing a request outside of the originally receiving thread? If you are 
actually operating within a web request and still receive this message, your 
code is probably running outside of DispatcherServlet/DispatcherPortlet: In 
this case, use RequestContextListener or 
RequestContextFilter to expose the current request.

我该如何解决?

推荐答案

HttpSession对象本身可以在多个线程中使用(但不是线程安全的，因此必须同步).但是Spring正在做一些额外的魔术，例如当您具有session范围的bean时.即，它使用下面的ThreadLocal来将当前会话与线程绑定.

The HttpSession object itself can be used in multiple threads (but is not thread-safe and therefore must be synchronized). However Spring is doing some extra magic e.g. when you have session-scoped beans. Namely it uses ThreadLocal underneath to bind current session with thread.

我不知道您的确切情况是什么，但是显然，当您在另一个线程中时，Spring会尝试从此ThreadLocal中检索HttpSession-显然会失败.

I don't know what is your exact scenario, but apparently Spring tries to retrieve HttpSession from this ThreadLocal while you are in another thread - which obviously fails.

解决方案很简单-在@Async方法中提取所需的会话属性，然后直接传递它们.顺便说一下，这是更好的设计-避免传递HttpSession对象，因为这会使测试变得更加困难，并且将来代码的重用性也将大大降低.

The solution is simple - extract session attributes you need in @Async method and pass them directly. This is by the way much better design - avoid passing HttpSession object around because it makes testing harder and your code is much less likely to be reused in the future.

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