<!-- https://mvnrepository.com/artifact/org.jasig.cas.client/cas-client-core --><dependency><groupId>org.jasig.cas.client</groupId><artifactId>cas-client-core</artifactId><version>3.2.0</version></dependency>        

<!-- 用于单点退出，该过滤器用于实现单点登出功能，可选配置 --><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></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，必须配置 --><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>单点登录系统认证接口</param-value></init-param><init-param><param-name>serverName</param-name><param-value>本业务系统首页地址</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>单点登录系统认证接口</param-value></init-param><init-param><param-name>serverName</param-name><param-value>本业务系统首页地址</param-value></init-param></filter><filter-mapping><filter-name>CAS Validation Filter</filter-name><url-pattern>/*</url-pattern></filter-mapping><!-- 该过滤器负责实现HttpServletRequest请求的包裹， 比如允许开发者通过HttpServletRequest的getRemoteUser()方法获得SSO登录用户的登录名，可选配置。 --><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><!-- 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>

@Overridepublic void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {HttpServletRequest re = (HttpServletRequest) request; //获取requestHttpServletResponse resp = (HttpServletResponse) response; //获取respinse
    AttributePrincipal attributePrincipal = (AttributePrincipal) re.getUserPrincipal(); //返回一个java.security.Principal  对象，该对象包含当前授权用户的名称String cas_account = "";String username = "";String userpass = "";//提前session中的登录信息Object object = re.getSession().getAttribute("_const_cas_assertion_");if (object != null) {Assertion assertion = (Assertion) object;fnumber = assertion.getPrincipal().getName();} else if (attributePrincipal != null) {cas_account = (String) attributePrincipal.getName();}Users userLogin = (Users) re.getSession().getAttribute("CURRENT_USER");if (userLogin == null) {if(cas_account ==null||"".equals(cas_account )){chain.doFilter(request, response);//本系统通过拦截器进行了登录状态校验，故此处放行，让后面的拦截器进行未登录重定向，而不在此处进行。当然，也可以在此处直接重定向回首页
            }}else{chain.doFilter(request, response);//若检测到登录信息，则直接放行
        }//检测到cas信息，但是又未登录，则在此处模拟登录过程    try {if (re.getSession().getAttribute("CURRENT_USER") == null) {//代码模拟登录过程：根据cas传过来的用户信息，查找本系统用户，拿到账号密码进行登录认证　　　　　　　　　　　模拟过程略......各系统不一样，按需实现。re.getSession().setAttribute("CURRENT_USER", 当前登录用户);resp.sendRedirect("/index?userId="+当前登录用户id);//登录成功，重定向到业务系统首页}else {if(users.size() == 0){logger.error("========users match none!========");//根据cas信息，在本系统没找到匹配用户，则返回系统登录页面或者重定向到一个错误提示页}else {logger.error("========users match more than one!========");//根据cas信息，在本系匹配到多于一个用户，则返回系统登录页面或者重定向到一个错误提示页
                            }}}} else {if(mobiles.size() == 0){logger.error("========mobile match none!========");}else {logger.error("========mobile match more than one!========");}}}} catch (Exception e) {e.printStackTrace();}chain.doFilter(request, response);}