SpringSecurity本身已经做好了与CAS的集成工作，只需要我们做简单配置就可以了

步骤1 spring-cas.xml配置文件内容如下(完整版)

1. <?xml version="1.0" encoding="UTF-8"?>
2. <beans:beans xmlns="http://www.springframework.org/schema/security"
3. xmlns:context="http://www.springframework.org/schema/context"
4. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
5. xmlns:beans="http://www.springframework.org/schema/beans"
6. xsi:schemaLocation="  http://www.springframework.org/schema/context  http://www.springframework.org/schema/context/spring-context-2.5.xsd
7. http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
8. http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.0.xsd"
9. default-lazy-init="true">
10. <context:component-scan base-package="com.itec.core" />
11. <!--SSO -->
12. <http auto-config="false" entry-point-ref="casEntryPoint" servlet-api-provision="true">
13. <intercept-url pattern="/login.do" filters="none" />
14. <intercept-url pattern="/image.do" filters="none" />
15. <intercept-url pattern="/admin/*.do*" access="ROLE_LOGIN" />
16. <!-- logout-success-url="/login.html" -->
17. <!--        <logout logout-url="/login.do" success-handler-ref="casLogoutSuccessHandler"/>   -->
18. <custom-filter ref="requestSingleLogoutFilter" before="LOGOUT_FILTER" />
19. <custom-filter position="FORM_LOGIN_FILTER" ref="casFilter"/>
20. <custom-filter ref="singleLogoutFilter" before="CAS_FILTER" />
21. </http>
22. <beans:bean id="casEntryPoint"  class="org.springframework.security.cas.web.CasAuthenticationEntryPoint">
23. <beans:property name="loginUrl" value="http://172.19.50.21:9083/HASLSSO/login"/>
24. <beans:property name="serviceProperties" ref="serviceProperties"/>
25. </beans:bean>
26. <beans:bean id="serviceProperties"  class="org.springframework.security.cas.ServiceProperties">
27. <beans:property name="service"  value="http://172.19.4.225:8080/HACMS/j_spring_cas_security_check"/>
28. <beans:property name="sendRenew" value="false"/>
29. </beans:bean>
30. <beans:bean id="casFilter"  class="org.springframework.security.cas.web.CasAuthenticationFilter">
31. <beans:property name="authenticationManager" ref="authenticationManager"/>
32. </beans:bean>
33. <authentication-manager alias="authenticationManager">
34. <authentication-provider ref="casAuthenticationProvider"/>
35. </authentication-manager>
36. <beans:bean id="casAuthenticationUserDetailsService" class="org.springframework.security.core.userdetails.UserDetailsByNameServiceWrapper">
37. <beans:property name="userDetailsService" >
38. <beans:ref bean="userDetailsManager" />
39. </beans:property>
40. </beans:bean>
41. <beans:bean id="casAuthenticationProvider"
42. class="org.springframework.security.cas.authentication.CasAuthenticationProvider">
43. <beans:property name="authenticationUserDetailsService" ref="casAuthenticationUserDetailsService"/>
44. <beans:property name="serviceProperties" ref="serviceProperties" />
45. <beans:property name="ticketValidator">
46. <beans:bean class="org.jasig.cas.client.validation.Cas20ServiceTicketValidator">
47. <beans:constructor-arg index="0" value="http://172.19.50.21:9083/HASLSSO" />
48. </beans:bean>
49. </beans:property>
50. <beans:property name="key" value="an_id_for_this_auth_provider_only"/>
51. </beans:bean>
52. <!-- 注销客户端 -->
53. <beans:bean id="singleLogoutFilter" class="org.jasig.cas.client.session.SingleSignOutFilter" />
54. <!-- 注销服务器端 -->
55. <beans:bean id="requestSingleLogoutFilter"
56. class="org.springframework.security.web.authentication.logout.LogoutFilter">
57. <beans:constructor-arg
58. value="http://172.19.50.21:9083/HASLSSO/logout" />
59. <beans:constructor-arg>
60. <beans:bean
61. class="org.springframework.security.web.authentication.logout.SecurityContextLogoutHandler"/>
62. </beans:constructor-arg>
63. <beans:property name="filterProcessesUrl" value="/j_spring_cas_security_logout" />
64. </beans:bean>
65. </beans:beans>

步骤2 之前的UserDetailsManager不需要改任何代码

1. @Service
2. public class UserDetailsManager implements UserDetailsService {

步骤3 web.xml需要修改一点东西，不加载Security的配置文件就行了

1. <context-param>
2. <param-name>contextConfigLocation</param-name>
3. <!-- 使用工程本身验证 -->
4. <param-value>/WEB-INF/spring-config.xml,/WEB-INF/spring-freemarker.xml,/WEB-INF/spring-jpa.xml,/WEB-INF/spring-security.xml</param-value>
5. <!-- 使用 SSO 验证 -->
6. <!--        <param-value>/WEB-INF/spring-config.xml,/WEB-INF/spring-freemarker.xml,/WEB-INF/spring-jpa.xml,/WEB-INF/spring-cas.xml</param-value> -->
7. </context-param>

大功告成~！