引入依赖

打开pox.xml

<dependency>  
       <groupId>org.springframework.security</groupId>  
       <artifactId>spring-security-cas</artifactId>  
       <version>4.1.0.RELEASE</version>  
</dependency>     
<dependency>  
        <groupId>org.jasig.cas.client</groupId>  
        <artifactId>cas-client-core</artifactId>  
        <version>3.3.3</version>  
        <exclusions>  
            <exclusion>  
                <groupId>org.slf4j</groupId>  
                <artifactId>log4j-over-slf4j</artifactId>  
            </exclusion>  
        </exclusions>  
</dependency> 

修改spring-security.xml

修改spring-security.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/security"
    xmlns:beans="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                        http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security.xsd">
    
    <!--   entry-point-ref  入口点引用 -->
    <http use-expressions="false" entry-point-ref="casProcessingFilterEntryPoint">  
        <intercept-url pattern="/**" access="ROLE_USER"/>   
        <csrf disabled="true"/>  
        <!-- custom-filter为过滤器， position 表示将过滤器放在指定的位置上，before表示放在指定位置之前  ，after表示放在指定的位置之后  -->           
        <custom-filter ref="casAuthenticationFilter"  position="CAS_FILTER" />      
        <custom-filter ref="requestSingleLogoutFilter" before="LOGOUT_FILTER"/>  
        <custom-filter ref="singleLogoutFilter" before="CAS_FILTER"/>  
    </http>
    
      <!-- CAS入口点 开始 -->
    <beans:bean id="casProcessingFilterEntryPoint" class="org.springframework.security.cas.web.CasAuthenticationEntryPoint">  
        <!-- 单点登录服务器登录URL -->  
        <beans:property name="loginUrl" value="http://localhost:9100/cas/login"/>  
        <beans:property name="serviceProperties" ref="serviceProperties"/>  
    </beans:bean>      
    <beans:bean id="serviceProperties" class="org.springframework.security.cas.ServiceProperties">  
        <!--service 配置自身工程的根地址+/login/cas   -->  
        <beans:property name="service" value="http://localhost:9003/login/cas"/>
    </beans:bean>  
    <!-- CAS入口点 结束 -->
   
    <!-- 认证过滤器 开始 -->
    <beans:bean id="casAuthenticationFilter" class="org.springframework.security.cas.web.CasAuthenticationFilter">  
        <beans:property name="authenticationManager" ref="authenticationManager"/>  
    </beans:bean>  
        <!-- 认证管理器 -->
    <authentication-manager alias="authenticationManager">
        <authentication-provider  ref="casAuthenticationProvider">
        </authentication-provider>
    </authentication-manager>
        <!-- 认证提供者 -->
    <beans:bean id="casAuthenticationProvider"     class="org.springframework.security.cas.authentication.CasAuthenticationProvider">  
        <beans:property name="authenticationUserDetailsService">  
            <beans:bean class="org.springframework.security.core.userdetails.UserDetailsByNameServiceWrapper">  
                <beans:constructor-arg ref="userDetailsService" />  
            </beans:bean>  
        </beans:property>  
        <beans:property name="serviceProperties" ref="serviceProperties"/>  
        <!-- ticketValidator 为票据验证器 -->
        <beans:property name="ticketValidator">  
            <beans:bean class="org.jasig.cas.client.validation.Cas20ServiceTicketValidator">  
                <beans:constructor-arg index="0" value="http://localhost:9100/cas"/>  
            </beans:bean>  
        </beans:property>  
        <beans:property name="key" value="an_id_for_this_auth_provider_only"/> 
    </beans:bean>        
            <!-- 认证类 -->
    <beans:bean id="userDetailsService" class="cn.itcast.demo.service.UserDetailServiceImpl"/>  
    
    <!-- 认证过滤器 结束 -->
    <!-- 单点登出  开始  -->     
    <beans:bean id="singleLogoutFilter" class="org.jasig.cas.client.session.SingleSignOutFilter"/>          
    <beans:bean id="requestSingleLogoutFilter" class="org.springframework.security.web.authentication.logout.LogoutFilter">  
        <beans:constructor-arg value="http://localhost:9100/cas/logout?service=http://www.baidu.com"/>  
        <beans:constructor-arg>  
            <beans:bean class="org.springframework.security.web.authentication.logout.SecurityContextLogoutHandler"/>  
        </beans:constructor-arg>  
        <beans:property name="filterProcessesUrl" value="/logout/cas"/>  
    </beans:bean>  
    <!-- 单点登出  结束 -->  
</beans:beans>

创建UserDetailsServiceImpl

3）创建UserDetailsServiceImpl

package cn.itcast.demo.service;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import org.springframework.security.core.GrantedAuthority;
import org.springframework.security.core.authority.SimpleGrantedAuthority;
import org.springframework.security.core.userdetails.User;
import org.springframework.security.core.userdetails.UserDetails;
import org.springframework.security.core.userdetails.UserDetailsService;
import org.springframework.security.core.userdetails.UsernameNotFoundException;

public class UserDetailServiceImpl implements UserDetailsService {

    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        System.out.println("经过认证类:"+username);
        
        List<GrantedAuthority> authorities=new ArrayList();
        authorities.add(new SimpleGrantedAuthority("ROLE_USER"));
        
        return new User(username,"",authorities);
    }

}

这个类的主要作用是在登陆后得到用户名，可以根据用户名查询角色或执行一些逻辑。

获取登录名

1.获取登录名
我们在处理后端逻辑需要获得登录名，那么如何获取单点登录的用户名呢? 其实和我们之前获得用户名的方式是完全相同的，我们下面来做个测试。
web.xml 添加springmvc

<servlet>
      <servlet-name>springmvc</servlet-name>
      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
      <!-- 指定加载的配置文件 ，通过参数contextConfigLocation加载-->
      <init-param>
          <param-name>contextConfigLocation</param-name>
          <param-value>classpath:springmvc.xml</param-value>
      </init-param>
  </servlet>
  
  <servlet-mapping>
      <servlet-name>springmvc</servlet-name>
      <url-pattern>*.do</url-pattern>
  </servlet-mapping>

创建springmvc.xml

2.创建springmvc.xml

<context:component-scan base-package="songzixian.com" />
<mvc:annotation-driven />

创建UserController

3.创建UserController

@RestController
public class UserController {
    @RequestMapping("/findLoginUser")
    public void  findLoginUser(){
        String name = SecurityContextHolder.getContext().getAuthentication().getName();
        System.out.println(name);        
    }    
}

地址栏输入http://localhost:9003/findLoginUser.do 即可在控制台看到输出的登录名

退出登录

1.修改spring-security.xml

<beans:bean id="requestSingleLogoutFilter" class="org.springframework.security.web.authentication.logout.LogoutFilter">  
        <beans:constructor-arg value="http://localhost:9100/cas/logout?service=http://localhost:9003/index2.html"/>  
        <beans:constructor-arg>  
            <beans:bean class="org.springframework.security.web.authentication.logout.SecurityContextLogoutHandler"/>  
        </beans:constructor-arg>  
        <beans:property name="filterProcessesUrl" value="/logout/cas"/>  
</beans:bean>

在页面上添加链接

<a href="/logout/cas">退出登录</a>

创建index2.html,将index2.html设置为可匿名访问

<http pattern="/index2.html" security="none"></http>