CAS实现SSO单点登录

环境

cas-server-4.1.8，cas-client-3.4.0，Java-8，Maven-3，Tomcat-7.0.72

CAS Server 安装

点此进入 CAS 下载列表，选择下载 cas-4.1.8.zip。

解压缩 cas-4.1.8.zip 并进入 cas-server-webapp 目录，在当前目录打开 cmd 并执行安装命令。

mvn -e -ff clean install -Dmaven.test.skip=true

经亲身测试（自己拉的电信12M网络），该安装过程非常漫长，主要因为镜像原因导致依赖包下载非常慢，此过程需静心等待。或直接下载我已经打好包的 cas.war 文件（注：该文件的依赖包版本有稍做修改，此不影响正常使用）。

安装完成后，在 cas-server-webapp/target 目录下可以看到 cas.war 文件，该文件便是 cas server 应用服务的 war 包。

cas server 安全认证是基于 https 的，这里使用 JDK 自带的 keytool 工具生成数字证书，生产环境系统的应用需要到证书提供商处购买证书。证书的生成及 Tomcat 的配置可参考文章：keytool 生成数字证书 – tomcat https 配置。

首先确保 Tomcat 的 https 可以正常访问，将 cas.war 文件拷贝到 apache-tomcat-7.0.72/webapps 下进行发布，启动 Tomcat，访问 https://www.fanlychie.com:8443/cas。

上图是用火狐浏览器打开的链接，选择高级 -> 添加例外 -> 确认安全例外。

用户名和密码在 apache-tomcat-7.0.72/webapps/cas/WEB-INF/deployerConfigContext.xml 配置文件中，找到并打开该文件，大概在 105 行

<bean id="primaryAuthenticationHandler"
    class="org.jasig.cas.authentication.AcceptUsersAuthenticationHandler">
    <property name="users">
        <map>
            <entry key="casuser" value="Mellon" />
        </map>
    </property>
</bean>

可以看到默认的用户名是 casuser，密码是 Mellon。

看到上图的页面，表明 cas server 已经部署成功。

CAS Server 配置基于数据库用户认证

回到 cas-4.1.8.zip 解压缩的目录，并进入 cas-server-support-jdbc 目录，在当前目录打开 cmd 并执行安装命令

mvn -e -ff clean install -Dmaven.test.skip=true

安装完成后在 target 目录得到 cas-server-support-jdbc-4.1.8.jar 文件。

将该文件拷贝到 apache-tomcat-7.0.72/webapps/cas/WEB-INF/lib 目录下，并向此目录添加c3p0-0.9.1.2.jar，mysql-connector-java-5.1.17.jar 两个文件。嫌麻烦的话，点此下载这三个 jar 包的压缩包文件。

再次打开 apache-tomcat-7.0.72/webapps/cas/WEB-INF/deployerConfigContext.xml 文件，大概在第 54 行。

<bean id="authenticationManager" class="org.jasig.cas.authentication.PolicyBasedAuthenticationManager">
    <constructor-arg>
        <map>
            <!--
               | IMPORTANT
               | Every handler requires a unique name.
               | If more than one instance of the same handler class is configured, you must explicitly
               | set its name to something other than its default name (typically the simple class name).
               -->
            <entry key-ref="proxyAuthenticationHandler" value-ref="proxyPrincipalResolver" />
            <!-- 注销此项
            <entry key-ref="primaryAuthenticationHandler" value-ref="primaryPrincipalResolver" />
            -->
            <!-- 添加此项 -->
            <entry key-ref="myAuthenticationHandler" value-ref="primaryPrincipalResolver" />
        </map>
    </constructor-arg>
    <!-- Uncomment the metadata populator to capture the password.
    <property name="authenticationMetaDataPopulators">
       <util:list>
           <bean class="org.jasig.cas.authentication.CacheCredentialsMetaDataPopulator"/>
       </util:list>
    </property>
    -->
    <!--
       | Defines the security policy around authentication. Some alternative policies that ship with CAS:
       |
       | * NotPreventedAuthenticationPolicy - all credential must either pass or fail authentication
       | * AllAuthenticationPolicy - all presented credential must be authenticated successfully
       | * RequiredHandlerAuthenticationPolicy - specifies a handler that must authenticate its credential to pass
       -->
    <property name="authenticationPolicy">
        <bean class="org.jasig.cas.authentication.AnyAuthenticationPolicy" />
    </property>
</bean>

按以上配置注销掉第二个 entry 并添加一个 entry。接着在后面添加两个 bean 配置。

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource" destroy-method="close">
    <property name="jdbcUrl" value="jdbc:mysql://127.0.0.1:3306/cas_test_db?autoReconnect=true&amp;useUnicode=true&amp;characterEncoding=utf-8" />
    <property name="user" value="root" />
    <property name="password" value="root" />
    <property name="driverClass" value="com.mysql.jdbc.Driver" />
    <property name="initialPoolSize" value="10" />
    <property name="maxIdleTime" value="1800" />
    <property name="maxPoolSize" value="60" />
    <property name="acquireIncrement" value="5" />
    <property name="acquireRetryAttempts" value="60" />
    <property name="acquireRetryDelay" value="2000" />
    <property name="breakAfterAcquireFailure" value="false" />
    <property name="autoCommitOnClose" value="false" />
    <property name="checkoutTimeout" value="30000" />
    <property name="idleConnectionTestPeriod" value="900" />
</bean>
<bean id="myAuthenticationHandler" class="org.jasig.cas.adaptors.jdbc.QueryDatabaseAuthenticationHandler"
    p:dataSource-ref="dataSource"
    p:sql="SELECT passwd FROM user WHERE name = ?" />

其中 cas_test_db 数据库中的 user 建表语句为

CREATE TABLE `user` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  `passwd` varchar(255) NOT NULL,
  PRIMARY KEY (`id`)
)

重启 Tomcat，访问 https://www.fanlychie.com:8443/cas，用数据库中的 name/passwd 作为用户名和密码登录系统，若登录成功，表明配置已成功。

CAS Client 客户端使用和配置

使用 maven 创建两个 web 项目 cas-client1，cas-client2。点此下载 demo 文件。

cas-client1 项目 pom.xml 配置

<dependencies>
    <dependency>
        <groupId>org.jasig.cas.client</groupId>
        <artifactId>cas-client-core</artifactId>
        <version>3.4.0</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.7.12</version>
    </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.apache.tomcat.maven</groupId>
            <artifactId>tomcat7-maven-plugin</artifactId>
            <version>2.2</version>
            <configuration>
                <path>/</path>
                <port>8881</port>
                <httpsPort>8081</httpsPort>
                <uriEncoding>UTF-8</uriEncoding>
                <protocol>org.apache.coyote.http11.Http11NioProtocol</protocol>
                <clientAuth>false</clientAuth>
                <keystoreFile>C:\Users\fanlychie\.keystore\selfissue.jks</keystoreFile>
                <keystorePass>123654</keystorePass>
                <keystoreType>JKS</keystoreType>
                <url>http://localhost:8081/manager/html</url>
            </configuration>
        </plugin>
    </plugins>
</build>

首先必须确保项目 https 协议可以正常访问，否则 cas server 无法认证。

选中项目 -> Run As -> Maven build… -> tomcat7:run

访问 https://www.fanlychie.com:8081，若能访问到，表明 Tomcat 已准备好。

cas-client1 项目 web.xml 配置

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <listener>
        <listener-class>org.jasig.cas.client.session.SingleSignOutHttpSessionListener</listener-class>
    </listener>
 
    <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>
            <!-- 此处配置的是 cas server 地址 -->
            <param-value>https://www.fanlychie.com:8443/cas</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CAS Single Sign Out Filter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
 
    <filter>
        <filter-name>CAS Authentication Filter</filter-name>
        <filter-class>org.jasig.cas.client.authentication.AuthenticationFilter</filter-class>
        <init-param>
            <param-name>casServerLoginUrl</param-name>
            <!-- 此处配置的是 cas server 登录地址 -->
            <param-value>https://www.fanlychie.com:8443/cas/login</param-value>
        </init-param>
        <init-param>
            <param-name>serverName</param-name>
            <!-- 此处配置的是当前项目地址, 且必须使用 https 服务, 否则 cas server 无法认证 -->
            <param-value>https://www.fanlychie.com:8081</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CAS Authentication Filter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <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>
            <!-- 此处配置的是 cas server 地址 -->
            <param-value>https://www.fanlychie.com:8443/cas</param-value>
        </init-param>
        <init-param>
            <param-name>serverName</param-name>
            <!-- 此处配置的是当前项目地址, 且必须使用 https 服务, 否则 cas server 无法认证 -->
            <param-value>https://www.fanlychie.com:8081</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>CAS Validation Filter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>
    <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>
    <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>
    <welcome-file-list>
        <welcome-file>index.jsp</welcome-file>
    </welcome-file-list>
</web-app>