shiro：缓存管理

1、

书写打印语句，运行查看打印的次数，从而获取到代码执行的次数：

    @Override
    protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principalCollection) {
        //获取用户的用户名，跟doGetAuthenticationInfo方法中的new SimpleAuthenticationInfo参数是对应的
        String username= (String) principalCollection.iterator().next();
        //根据用户名查询当前用户的前台列表
        Set<String> roleNames=roleDao.queryRoleNameByUsername(username);
        Set<String> ps=permissionDao.queryPermissionsByUsername(username);
        SimpleAuthorizationInfo info=new SimpleAuthorizationInfo();
        info.setRoles(roleNames);
        info.setStringPermissions(ps);
        System.out.println("查询用户及权限信息");
        return info;
    }

从打印结果来看，代码执行了多次，使用Shiro进行权限管理过程中，每次授权都会访问realm中的doGetAuthorizationInfo方法查询当前用户的角色及权限信息，如果系统的用户量比较大则会对教据库造威比较大的压力（会对所有的权限进行一次比较）

2020-09-29 15:22:04.150  INFO 11984 --- [           main] com.zhb.test.DemoApplication             : Started DemoApplication in 6.44 seconds (JVM running for 7.9)
2020-09-29 15:22:09.717  INFO 11984 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2020-09-29 15:22:09.717  INFO 11984 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2020-09-29 15:22:09.732  INFO 11984 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 15 ms
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@718a383c] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: select * from tb_users where username=? 
==> Parameters: zhai(String)
<==    Columns: user_id, username, password, password_salt
<==        Row: 1, zhai, ae1de49a9f24d38da38f7afe9ce70db4, 68795
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@718a383c]
成功
zhai123
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@143272b] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT role_name FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: role_name
<==        Row: 学生
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@143272b]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@394df695] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT tb_permissions.permission_code FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id INNER JOIN tb_rps ON tb_roles.role_id = tb_rps.rid INNER JOIN tb_permissions ON tb_rps.pid = tb_permissions.permission_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: permission_code
<==        Row: stu_select
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@394df695]
查询用户及权限信息
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@26d7596d] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT role_name FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: role_name
<==        Row: 学生
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@26d7596d]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@103bb341] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT tb_permissions.permission_code FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id INNER JOIN tb_rps ON tb_roles.role_id = tb_rps.rid INNER JOIN tb_permissions ON tb_rps.pid = tb_permissions.permission_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: permission_code
<==        Row: stu_select
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@103bb341]
查询用户及权限信息
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7436aff4] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT role_name FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: role_name
<==        Row: 学生
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@7436aff4]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@79afc66a] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT tb_permissions.permission_code FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id INNER JOIN tb_rps ON tb_roles.role_id = tb_rps.rid INNER JOIN tb_permissions ON tb_rps.pid = tb_permissions.permission_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: permission_code
<==        Row: stu_select
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@79afc66a]
查询用户及权限信息
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6430afc2] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT role_name FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: role_name
<==        Row: 学生
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6430afc2]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@49d3c55e] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT tb_permissions.permission_code FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id INNER JOIN tb_rps ON tb_roles.role_id = tb_rps.rid INNER JOIN tb_permissions ON tb_rps.pid = tb_permissions.permission_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: permission_code
<==        Row: stu_select
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@49d3c55e]
查询用户及权限信息
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1db031b7] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT role_name FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: role_name
<==        Row: 学生
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@1db031b7]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5c691bd4] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT tb_permissions.permission_code FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id INNER JOIN tb_rps ON tb_roles.role_id = tb_rps.rid INNER JOIN tb_permissions ON tb_rps.pid = tb_permissions.permission_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: permission_code
<==        Row: stu_select
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5c691bd4]
查询用户及权限信息
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@669b4a4a] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT role_name FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: role_name
<==        Row: 学生
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@669b4a4a]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@477cdf24] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT tb_permissions.permission_code FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id INNER JOIN tb_rps ON tb_roles.role_id = tb_rps.rid INNER JOIN tb_permissions ON tb_rps.pid = tb_permissions.permission_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: permission_code
<==        Row: stu_select
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@477cdf24]
查询用户及权限信息
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5617431d] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT role_name FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: role_name
<==        Row: 学生
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5617431d]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@247ce7cd] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT tb_permissions.permission_code FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id INNER JOIN tb_rps ON tb_roles.role_id = tb_rps.rid INNER JOIN tb_permissions ON tb_rps.pid = tb_permissions.permission_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: permission_code
<==        Row: stu_select
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@247ce7cd]
查询用户及权限信息
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4a94583f] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT role_name FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: role_name
<==        Row: 学生
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@4a94583f]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6775981e] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@6b0efb9] will not be managed by Spring
==>  Preparing: SELECT tb_permissions.permission_code FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id INNER JOIN tb_rps ON tb_roles.role_id = tb_rps.rid INNER JOIN tb_permissions ON tb_rps.pid = tb_permissions.permission_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: permission_code
<==        Row: stu_select
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@6775981e]
查询用户及权限信息

2、缓存的使用

Shiro支持缓存以降低对数据库的访问压力〔缓存的是授权信息)

（1）导入依赖

 <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>mybatis-spring-boot-cache</artifactId>
        </dependency>
        <!--第三方缓存的支持-->
        <dependency>
            <groupId>net.sf.ehcache</groupId>
            <artifactId>ehcache</artifactId>
        </dependency>
        <!--shiro对缓存的支持-->
        <dependency>
            <groupId>org.apache.shiro</groupId>
            <artifactId>shiro-ehcache</artifactId>
            <version>1.4.0</version>
 </dependency>

（2）配置缓存策略

<?xml version="1.0" encoding="UTF-8"?>
<ehcache updateCheck="false" dynamicConfig="false">
    <diskStore path="C:	oolsehcache" />
    <defaultCache name="defaultCache"
            maxElementsInMemory="1000"
            eternal="false"
            timeToIdleSeconds="120"
            timeToLiveSeconds="120"
            overflowToDisk="false"
            maxElementsOnDisk="100000"
            diskPersistent="false"
            diskExpiryThreadIntervalSeconds="120"
            memoryStoreEvictionPolicy="LRU">
    </defaultCache>
</ehcache>

• diskStore：缓存数据持久化的目录
• eternal：缓存中对象是否为永久的，如果是，超时设置将被忽略，对象从不过期。
• maxElementsInMemory：缓存中允许创建的最大对象数
• overflowToDisk：内存不足时，是否启用磁盘缓存。
• timeToIdleSeconds：缓存数据的钝化时间，也就是在一个元素消亡之前， 两次访问时间的最大时间间隔值，这只能在元素不是永久驻留时有效，如果该值是 0 就意味着元素可以停顿无穷长的时间。
• timeToLiveSeconds：缓存数据的生存时间，也就是一个元素从构建到消亡的最大时间间隔值，这只能在元素不是永久驻留时有效，如果该值是0就意味着元素可以停顿无穷长的时间。
• memoryStoreEvictionPolicy：缓存满了之后的淘汰算法。
• diskPersistent:设定在虚拟机重启时是否进行磁盘存储，默认为false
• diskExpiryThreadIntervalSeconds: 属性可以设置该线程执行的间隔时间(默认是120秒，不能太小

FIFO，先进先出
LFU，最少被使用，缓存的元素有一个hit属性，hit值最小的将会被清出缓存。
LRU，最近最少使用的，缓存的元素有一个时间戳，当缓存容量满了，而又需要腾出地方来缓存新的元素的时候，那么现有缓存元素中时间戳离当前时间最远的元素将被清出缓存。

（3）配置缓存管理器

配置缓存管理器：

   @Bean
    public EhCacheManager getEhCacheManager(){
        EhCacheManager ehCacheManager=new EhCacheManager();
        ehCacheManager.setCacheManagerConfigFile("classpath:ehcache.xml");
        return ehCacheManager;
    }

将缓存管理器交给SecurityManager：

   @Bean//安全管理器
    public DefaultWebSecurityManager getDefaultWebSecurityManager(MyRealm myRealm,EhCacheManager ehCacheManager) {
        DefaultWebSecurityManager defaultSecurityManager = new DefaultWebSecurityManager();
        defaultSecurityManager.setRealm(myRealm);//SecurityManager完成校验需要realm
        defaultSecurityManager.setCacheManager(ehCacheManager);
        return defaultSecurityManager;
    }

（4）测试

Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@37f849de]
成功
zhai123
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5e7d8fd8] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@2b0be8da] will not be managed by Spring
==>  Preparing: SELECT role_name FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: role_name
<==        Row: 学生
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@5e7d8fd8]
Creating a new SqlSession
SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@8ed5890] was not registered for synchronization because synchronization is not active
JDBC Connection [com.alibaba.druid.proxy.jdbc.ConnectionProxyImpl@2b0be8da] will not be managed by Spring
==>  Preparing: SELECT tb_permissions.permission_code FROM tb_users INNER JOIN tb_urs ON tb_users.user_id = tb_urs.uid INNER JOIN tb_roles ON tb_urs.rid = tb_roles.role_id INNER JOIN tb_rps ON tb_roles.role_id = tb_rps.rid INNER JOIN tb_permissions ON tb_rps.pid = tb_permissions.permission_id WHERE tb_users.username=? 
==> Parameters: zhai(String)
<==    Columns: permission_code
<==        Row: stu_select
<==      Total: 1
Closing non transactional SqlSession [org.apache.ibatis.session.defaults.DefaultSqlSession@8ed5890]
查询用户及权限信息