连接到mysql数据库，用的是druid的连接池。

需要导入三个jar包：

<!-- https://mvnrepository.com/artifact/com.alibaba/druid --><dependency><groupId>com.alibaba</groupId><artifactId>druid</artifactId><version>1.0.18</version></dependency><!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.38</version></dependency><!-- https://mvnrepository.com/artifact/commons-logging/commons-logging --><dependency><groupId>commons-logging</groupId><artifactId>commons-logging</artifactId><version>1.1.1</version></dependency>

jdbc_realm.ini

[main]
jdbcRealm=org.apache.shiro.realm.jdbc.JdbcRealm
dataSource=com.alibaba.druid.pool.DruidDataSource
dataSource.driverClassName=com.mysql.jdbc.Driver
dataSource.url=jdbc:mysql://localhost:3306/db_shiro
dataSource.username=root
dataSource.password=123456
jdbcRealm.dataSource=$dataSource
securityManager.realms=$jdbcRealm