cas认证登陆时报错，求高手指点

Question

java.lang.ClassCastException: org.jasig.cas.client.authentication.AttributePrincipalImpl cannot be cast to org.springframework.security.cas.authentication.CasAuthenticationToken
com.chinamobile.bcop.user.sso.UserInjectFilter.doFilter(UserInjectFilter.java:46)

UserInjectFilter.java:46的代码
CasAuthenticationToken principal = (CasAuthenticationToken) ((HttpServletRequest) httpRequest).getUserPrincipal();

Answer 1

http://zhidao.baidu.com/link?url=YUjjAtQmVgmyupreUAQ6ozXDS7FAR7LT5bUbHhVlXGp53xd6-cuPguDKgAcZO0h6dR2bbqwJXoT8hT0EoxQH-_