CAS是SSO常用的开源解决方案，可以适用多种语言实现的Web应用。前面介绍了CAS Server端的配置。下面结合本人的实际操作，详细说明下Java应用CAS Client配置。首先，说明下配置环境：
1. CAS Server 3.4.5，跑在tomcat 7上。 部署在http://www.cas.com/cas上(本地hosts文件配置域名)。
2. CAS Client Java SSH应用(Struts 2.3.4.1、Spring 3.0.5、Hibernate 3.3.2，如应用使用了特定安全框架如Spring Security，且集成了CAS Client,可直接使用其提供的配置方法), web应用也跑在tomcat 7上，部署在http://www.my.com/app(本地hosts文件配置域名)。
配置步骤：
1.添加cas-client-core-3.1.10-sources.jar，如使用mvn，pom.xml中添加
<dependency> <groupId>org.jasig.cas</groupId> <artifactId>cas-client-core</artifactId> <version>3.1.10</version> <exclusions> <exclusion> <artifactId>servlet-api</artifactId> <groupId>javax.servlet</groupId> </exclusion> </exclusions> </dependency>
2. web.xml中添加：
<!-- 与CAS Single Sign Out Filter配合，注销登录信息 -->
<listener>
<listener-class>org.jasig.cas.client.session.SingleSignOutHttpSessionListener</listener-class>
</listener>
<!-- CAS Server 通知 CAS Client，删除session,注销登录信息 -->
<filter>
<filter-name>CAS Single Sign Out Filter</filter-name>
<filter-class>org.jasig.cas.client.session.SingleSignOutFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>CAS Single Sign Out Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 登录认证，未登录用户导向CAS Server进行认证 -->
<filter>
<filter-name>CAS Filter</filter-name>
<filter-class>org.jasig.cas.client.authentication.AuthenticationFilter</filter-class>
<init-param>
<param-name>casServerLoginUrl</param-name>
<param-value>http://www.cas.com/cas/login</param-value>
</init-param>
<init-param>
<param-name>serverName</param-name>
<param-value>http://api.zfwx.com:8080</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CAS Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- CAS Client向CAS Server进行ticket验证 -->
<filter>
<filter-name>CAS Validation Filter</filter-name>
<filter-class>org.jasig.cas.client.validation.Cas20ProxyReceivingTicketValidationFilter</filter-class>
<init-param>
<param-name>casServerUrlPrefix</param-name>
<param-value>http://www.cas.com/cas</param-value>
</init-param>
<init-param>
<param-name>serverName</param-name>
<param-value>http://api.zfwx.com:8080</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CAS Validation Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 封装request, 支持getUserPrincipal等方法-->
<filter>
<filter-name>CAS HttpServletRequest Wrapper Filter</filter-name>
<filter-class>org.jasig.cas.client.util.HttpServletRequestWrapperFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>CAS HttpServletRequest Wrapper Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 存放Assertion到ThreadLocal中 -->
<filter>
<filter-name>CAS Assertion Thread Local Filter</filter-name>
<filter-class>org.jasig.cas.client.util.AssertionThreadLocalFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>CAS Assertion Thread Local Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
3. 编写个简单的测试页面test.jsp进行测试。
<%@ page import="org.jasig.cas.client.authentication.AttributePrincipal" %>
<html>
<head><title>cas test</title></head>
<body>
<%
AttributePrincipal principal = (AttributePrincipal)request.getUserPrincipal();
String username = principal.getName();
%>
<% if(null!=username){ %>
<h2>Hello <%=username %> !</h2>
<a href="http://www.cas.com/cas/logout">logout</a>
<% }%>
</body>
</html>