概要
在开发WEB程序时需要整合CAS实现单点登录，下面介绍一下应用整合CAS服务器的过程。
在开始之前，我们确定CAS服务器已经搭建完毕。
实现步骤
1.新建一个maven项目，引入casclient 包。
<dependency>
<groupId>org.jasig.cas.client</groupId>
<artifactId>cas-client-core</artifactId>
<version>3.5.1</version>
</dependency>
2.修改web.xml 文件。
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
<display-name>Archetype Created Web Application</display-name>
<listener>
<listener-class>org.jasig.cas.client.session.SingleSignOutHttpSessionListener</listener-class>
</listener>
<!-- 该过滤器用于实现单点登出功能，可选配置。 -->
<filter>
<filter-name>CAS Single Sign Out Filter</filter-name>
<filter-class>org.jasig.cas.client.session.SingleSignOutFilter</filter-class>
<init-param>
<param-name>casServerUrlPrefix</param-name>
<param-value>http://192.168.78.118:9000/cas</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CAS Single Sign Out Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 该过滤器负责用户的认证工作，必须启用它 -->
<filter>
<filter-name>CASFilter</filter-name>
<filter-class>org.jasig.cas.client.authentication.AuthenticationFilter</filter-class>
<init-param>
<param-name>casServerLoginUrl</param-name>
<param-value>http://192.168.78.118:9000/cas/login</param-value>
<!--这里的server是服务端的IP -->
</init-param>
<init-param>
<param-name>serverName</param-name>
<param-value>http://192.168.78.118:8080</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CASFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<!-- 该过滤器负责对Ticket的校验工作，必须启用它 -->
<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://192.168.78.118:9000/cas</param-value>
</init-param>
<init-param>
<param-name>serverName</param-name>
<param-value>http://192.168.78.118:8080</param-value>
</init-param>
</filter>
<filter-mapping>
<filter-name>CAS Validation Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping> <!-- 该过滤器使得开发者可以通过org.jasig.cas.client.util.AssertionHolder来获取用户的登录名。
比如AssertionHolder.getAssertion().getPrincipal().getName()。 -->
<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>
</web-app>
cas服务器访问地址：
http://192.168.78.118:9000/cas
平台访问地址前缀：
http://192.168.78.118:8080
3.编写一个index.jsp 页面。
<%@page import="org.jasig.cas.client.util.AssertionHolder"%>
<%@page contentType="text/html; charset=utf-8" %>
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<h2>欢迎 <%=AssertionHolder.getAssertion().getPrincipal().getName() %></h2>
<a href="http://192.168.78.118:9000/cas/logout?service=http://192.168.78.118:8080/demo">logout</a>
</body>
</html>
该页面实现了登陆后的当前用户账号的获取和用户退出系统登录。