CAS在登陆页停留过长时登陆后重回登陆页的问题

CAS停留在登陆页重复时间过长，导致重复登陆的情况：

调试源代码后发现是如下问题：

FlowHnadlerAdapter第183行报错导致了Spring直接302跳转。报错信息如下：

org.springframework.webflow.execution.repository.NoSuchFlowExecutionException: No flow execution could be found with key 'e1s1' -- perhaps this executing flow has ended or expired? This could happen if your users are relying on browser history (typically via the back button) that references ended flows.

认真检查了下，发现是web.xml中的session配置成了5分钟导致，将该数值调整至合适的值就不会出现该现象。