CAS安装好默认使用的是静态用户和密码，但实际使用中，我们可能连接LDAP、数据库等其他情况。接下来，我们看一下如何使用CAS连接Mysql数据库。

创建数据库

DROP TABLE IF EXISTS `users`;
CREATE TABLE  `users` (
  `username` varchar(50) NOT NULL,
  `password` varchar(50) NOT NULL,
  PRIMARY KEY (`username`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

insert into users values ('admin','123456');

配置

使用数据库需要cas-server-support-jdbc的支持，在此依赖中的目录cas-4.2.1/cas-server-support-jdbc/src/main/java/org/jasig/cas/adaptors/jdbc中有多类组件完成配置。以QueryDatabaseAuthenticationHandler为例，可参考官方文档

注意使用QueryDatabaseAuthenticationHandler作为数据验证方式需屏蔽一下类QueryAndEncodeDatabaseAuthenticationHandler，如下

QueryAndEncodeDatabaseAuthenticationHandler.java注释内容如下；

......
//import org.springframework.stereotype.Component;
......
//@Component("queryAndEncodeDatabaseAuthenticationHandler")
......

修改完成后进入目录cas-4.2.1/cas-server-support-jdbc，重新执行gradle clean build，生成jar包cas-4.2.1/cas-server-support-jdbc/build/libs/cas-server-support-jdbc-4.2.1.jar，并将此jar包放入webapps/cas/WEB-INF/lib中，由于本例使用mysql，所以需将mysql驱动包mysql-connector-java-5.1.25.jar也放到lib目录中。

接下来在文件webapps/cas/WEB-INF/deployerConfigContext.xml中增加以下配置，并注释掉一行

<bean id="dataSource"
  class="com.mchange.v2.c3p0.ComboPooledDataSource"
  p:driverClass="${database.driverClass}"
  p:jdbcUrl="${database.url}"
  p:user="${database.user}"
  p:password="${database.password}"
  p:initialPoolSize="${database.pool.minSize}"
  p:minPoolSize="${database.pool.minSize}"
  p:maxPoolSize="${database.pool.maxSize}"
  p:maxIdleTimeExcessConnections="${database.pool.maxIdleTime}"
  p:checkoutTimeout="${database.pool.maxWait}"
  p:acquireIncrement="${database.pool.acquireIncrement}"
  p:acquireRetryAttempts="${database.pool.acquireRetryAttempts}"
  p:acquireRetryDelay="${database.pool.acquireRetryDelay}"
  p:idleConnectionTestPeriod="${database.pool.idleConnectionTestPeriod}"
  p:preferredTestQuery="${database.pool.connectionHealthQuery}" />
  
  <alias name="queryDatabaseAuthenticationHandler" alias="primaryAuthenticationHandler" />
  <alias name="dataSource" alias="queryDatabaseDataSource" />
  
  <!--<alias name="acceptUsersAuthenticationHandler" alias="primaryAuthenticationHandler" />此行注释-->

接着配置/webapps/cas/WEB-INF/cas.properties，添加以下内容

# add by hode begin

# == Basic database connection pool configuration ==
database.driverClass=com.mysql.jdbc.Driver
database.url=jdbc:mysql://192.167.48.1:3306/hode
database.user=root
database.password=kroot
database.pool.minSize=6
database.pool.maxSize=18

# Maximum amount of time to wait in ms for a connection to become
# available when the pool is exhausted
database.pool.maxWait=10000

# Amount of time in seconds after which idle connections
# in excess of minimum size are pruned.
database.pool.maxIdleTime=120

# Number of connections to obtain on pool exhaustion condition.
# The maximum pool size is always respected when acquiring
# new connections.
database.pool.acquireIncrement=6

# == Connection testing settings ==

# Period in s at which a health query will be issued on idle
# connections to determine connection liveliness.
database.pool.idleConnectionTestPeriod=30

# Query executed periodically to test health
database.pool.connectionHealthQuery=select 1

# == Database recovery settings ==

# Number of times to retry acquiring a _new_ connection
# when an error is encountered during acquisition.
database.pool.acquireRetryAttempts=5

# Amount of time in ms to wait between successive aquire retry attempts.
database.pool.acquireRetryDelay=2000

# add by hode end

同时需取消注释项cas.jdbc.authn.query.sql，并添加sql语句

1	cas.jdbc.authn.query.sql=select password from users where username=?

配置完成。重启tomcat即可用hode/123456进行登录，完成验证。

当然文明密码保存到数据库中是相当不安全的，所以需要保存加密后的密码，配置如下，此时md5后的结果与数据库的密码进行比较

deployerConfigContext.xml增加一行
<alias name="defaultPasswordEncoder" alias="passwordEncoder" />

cas.properties增加两行
cas.authn.password.encoding.char=UTF-8
cas.authn.password.encoding.alg=MD5