前言

对于用户权限而言，它是不经常更改的，所以可以将用户的权限数据缓存到Redis或者Ehcache
部分摘自：https://mrbird.cc/Spring-Boot-Shiro%20cache.html

Shiro集成Redis

添加依赖

<!-- shiro-redis -->
<dependency>
    <groupId>org.crazycake</groupId>
    <artifactId>shiro-redis</artifactId>
    <version>2.4.2.1-RELEASE</version>
</dependency>

配置Redis

spring:
  redis:
    host: localhost
    port: 6379
    pool:
      max-active: 8
      max-wait: -1
      max-idle: 8
      min-idle: 0
    timeout: 0

ShiroConfig配置Redis

public RedisManager redisManager() {
    RedisManager redisManager = new RedisManager();
    //通过这里修改Redis的连接
    return redisManager;
}

public RedisCacheManager cacheManager() {
    RedisCacheManager redisCacheManager = new RedisCacheManager();
    redisCacheManager.setRedisManager(redisManager());
    return redisCacheManager;
}

最后在SecurityManager中加入RedisCacheManager：

@Bean  
public SecurityManager securityManager(){  
    DefaultWebSecurityManager securityManager =  new DefaultWebSecurityManager();
    ...
    securityManager.setCacheManager(cacheManager());
    return securityManager;  
}

启动成功之后，后台就会自己把获得的用户权限存到Redis中，之后你就会发现和之前相比的不同，如下图：
请求完三次接口

有缓存的请求：

无缓存的请求：

可以明显看出，他后面的请求从Redis中读取而不再去数据库了，这样的好处不再陈述！

Shiro集成Ehcache

添加依赖

<!-- shiro ehcache -->
<dependency>
    <groupId>org.apache.shiro</groupId>
    <artifactId>shiro-ehcache</artifactId>
    <version>1.3.2</version>
</dependency>
<!-- ehchache -->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-cache</artifactId>
</dependency>
<dependency>
    <groupId>net.sf.ehcache</groupId>
    <artifactId>ehcache</artifactId>
</dependency>

配置shiro-ehcache.xml

在src/main/resource/config路径下新增一个Ehcache配置shiro-ehcache.xml：

<?xml version="1.0" encoding="UTF-8"?>
<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:noNamespaceSchemaLocation="http://ehcache.org/ehcache.xsd"
    updateCheck="false">
    <diskStore path="java.io.tmpdir/Tmp_EhCache" />
    <defaultCache
        maxElementsInMemory="10000"
        eternal="false"
        timeToIdleSeconds="120"
        timeToLiveSeconds="120"
        overflowToDisk="false"
        diskPersistent="false"
        diskExpiryThreadIntervalSeconds="120" />
    
    <!-- 登录记录缓存锁定1小时 -->
    <cache 
        name="passwordRetryCache"
        maxEntriesLocalHeap="2000"
        eternal="false"
        timeToIdleSeconds="3600"
        timeToLiveSeconds="0"
        overflowToDisk="false"
        statistics="true" />
</ehcache>

ShiroConfig配置Ehcache

接着在ShiroConfig中注入Ehcache缓存：

@Bean
public EhCacheManager getEhCacheManager() {
    EhCacheManager em = new EhCacheManager();
    em.setCacheManagerConfigFile("classpath:config/shiro-ehcache.xml");
    return em;
}

将缓存对象注入到SecurityManager中：

@Bean  
public SecurityManager securityManager(){  
    DefaultWebSecurityManager securityManager =  new DefaultWebSecurityManager();
    securityManager.setRealm(shiroRealm());
    securityManager.setRememberMeManager(rememberMeManager());
    securityManager.setCacheManager(getEhCacheManager());
    return securityManager;  
}