SpringBoot 缓存管理器CacheManager
从3.1开始Spring定义了org.springframework.cache.Cache
和org.springframework.cache.CacheManager
接口来统一不同的缓存技术;并支持使用JCache(JSR-107)
注解简化开发.
- Cache接口为缓存的组件规范定义,包含缓存的各种操作集合;
- Cache接口下Spring提供了各种xxxCache的实现;如
RedisCache
,EhCacheCache
,ConcurrentMapCache
等;
快速开始
1、导入Maven
org.springframework.boot
spring-boot-starter-cache
org.springframework.boot
spring-boot-starter-data-redis
org.apache.commons
commons-pool2
因为需要用RedisCacheManager
所以导入Redis依赖
2、配置Redis并开启缓存支持
import com.fasterxml.jackson.annotation.JsonAutoDetect;
import com.fasterxml.jackson.annotation.PropertyAccessor;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CachingConfigurerSupport;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.redis.cache.RedisCacheConfiguration;
import org.springframework.data.redis.cache.RedisCacheManager;
import org.springframework.data.redis.connection.lettuce.LettuceConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.RedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import javax.annotation.Resource;
import java.time.Duration;
/**
*
* @author rstyro
* @time 2018-07-31
*
*/
@Configuration
@EnableCaching // 开启缓存支持
public class RedisConfig extends CachingConfigurerSupport {
@Resource
private LettuceConnectionFactory lettuceConnectionFactory;
/**
* 配置CacheManager
* @return
*/
@Bean
public CacheManager cacheManager() {
RedisSerializer redisSerializer = new StringRedisSerializer();
Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
//解决查询缓存转换异常的问题
ObjectMapper om = new ObjectMapper();
om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
jackson2JsonRedisSerializer.setObjectMapper(om);
// 配置序列化(解决乱码的问题)
RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
// .entryTtl(Duration.ZERO)
.entryTtl(Duration.ofSeconds(20)) //设置缓存失效时间
.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer))
.disableCachingNullValues();
RedisCacheManager cacheManager = RedisCacheManager.builder(lettuceConnectionFactory)
.cacheDefaults(config)
.build();
return cacheManager;
}
/**
* RedisTemplate配置
*/
@Bean
public RedisTemplate redisTemplate(LettuceConnectionFactory lettuceConnectionFactory) {
// 设置序列化
Jackson2JsonRedisSerializer
3、注解解析
注解的几个属性说明:
//指定缓存组件的名字
@AliasFor("cacheNames")
String[] value() default {};
//指定缓存组件的名字
@AliasFor("value")
String[] cacheNames() default {};
// 缓存数据使用的Key,
String key() default "";
// key的生成器,可以自己指定key的生成组件id;
// key 与 keyGenerator 两个只能选一个,不能同时指定
String keyGenerator() default "";
// 指定缓存管理器,
String cacheManager() default "";
//指定获得解析器,cacheManager、cacheResolver 两者取其一
String cacheResolver() default "";
// 符合condition条件,才缓存
String condition() default "";
// 和 codition 条件相反才成立
String unless() default "";
// 是否使用异步模式
boolean sync() default false;
// 只有@CacheEvict 有这个属性
// 清空所有缓存信息
boolean allEntries() default false;
// 只有@CacheEvict 有这个属性
// 缓存的清除是否在方法之前执行
// beforeInvocation=false 默认是在方法之后执行
boolean beforeInvocation() default false;
-
@Cacheable
先查询缓存中是否存在,存在则返回缓存内容,反正执行方法后返回并把返回结果缓存起来 -
@CacheEvict
删除指定缓存 -
@CachePut
更新并刷新缓存,先执行方法内容,然后更新缓存 -
@EnableCaching
这个是一个复合注解,可以拥有同时配置上面3个注解的功能
4、使用方法
@CacheConfig(cacheNames = "act") //这个注解表示类中共同放入到act 模块中
@Service
public class ActicleService implements IActicleService {
@Autowired
private ActicleMapper acticleMapper;
/**
* @Cacheable
* 1、先查缓存,
* 2、若没有缓存,就执行方法
* 3、若有缓存。则返回,不执行方法
*
* 所以@Cacheable 不能使用result
*
* @return
* @throws Exception
*/
@Cacheable(key = "#root.methodName")
public List list() throws Exception {
return acticleMapper.getActicleList();
}
/**
* @CachePut 更新并刷新缓存
* 1、先调用目标方法
* 2、把结果缓存
* @param acticle
* @return
* @throws Exception
*/
@CachePut(key = "#result.id" ,unless = "#result.id == null" )
public Acticle save(Acticle acticle) throws Exception {
acticle.setCreateBy(1l);
acticle.setCreateTime(LocalDateTime.now());
acticle.setModifyBy(1l);
acticle.setModifyTime(LocalDateTime.now());
acticleMapper.save(acticle);
System.out.println("acticle="+acticle);
return acticle;
}
/**
* 删除指定key 的缓存
* beforeInvocation=false 缓存的清除是否在方法之前执行
* 默认是在方法之后执行
* @param id
* @return
* @throws Exception
*/
@CacheEvict(key = "#id",beforeInvocation = true)
public int del(Long id) throws Exception {
int isDel = 0;
isDel = acticleMapper.del(id);
return isDel;
}
/**
* 删除所有缓存
* @return
* @throws Exception
*/
@CacheEvict(allEntries = true)
public int delAll() throws Exception {
return 1;
}
@CachePut(key = "#result.id" ,unless = "#result.id == null" )
public Acticle update(Acticle acticle) throws Exception {
acticle.setModifyBy(1l);
acticle.setModifyTime(LocalDateTime.now());
return acticleMapper.update(acticle);
}
@Cacheable(key = "#id",condition = "#id > 0")
public Acticle queryById(Long id) throws Exception {
return acticleMapper.queryById(id);
}
/**
* @Caching复杂组合缓存注解
*
* @param title
* @return
* @throws Exception
*/
@Caching(cacheable = { @Cacheable(key = "#title")},
put = {@CachePut(key = "#result.id"),
// @CachePut(key = "T(String).valueOf(#page).concat('-').concat(#pageSize)")
@CachePut(key = "T(String).valueOf('tag').concat('-').concat(#result.tagId)")
})
public Acticle queryByTitle(String title) throws Exception {
return acticleMapper.queryByTitle(title);
}
@Cacheable(key = "T(String).valueOf('tag').concat('-').concat(#tagId)")
public Acticle queryByTag(Long tagId) throws Exception {
return null;
}
}
缓存工作原理
当我们引入缓存的时候,SpringBoot的缓存自动配置CacheAutoConfiguration
就会生效
- 在
CacheAutoConfiguration
中的CacheConfigurationImportSelector
会导入很多缓存组件配置类 - 通过debug看源码,知道imports 的内容如下
static class CacheConfigurationImportSelector implements ImportSelector {
CacheConfigurationImportSelector() {
}
public String[] selectImports(AnnotationMetadata importingClassMetadata) {
CacheType[] types = CacheType.values();
String[] imports = new String[types.length];
for(int i = 0; i < types.length; ++i) {
imports[i] = CacheConfigurations.getConfigurationClass(types[i]);
}
return imports;
}
}
/**
imports 如下
0 = "org.springframework.boot.autoconfigure.cache.GenericCacheConfiguration"
1 = "org.springframework.boot.autoconfigure.cache.JCacheCacheConfiguration"
2 = "org.springframework.boot.autoconfigure.cache.EhCacheCacheConfiguration"
3 = "org.springframework.boot.autoconfigure.cache.HazelcastCacheConfiguration"
4 = "org.springframework.boot.autoconfigure.cache.InfinispanCacheConfiguration"
5 = "org.springframework.boot.autoconfigure.cache.CouchbaseCacheConfiguration"
6 = "org.springframework.boot.autoconfigure.cache.RedisCacheConfiguration"
7 = "org.springframework.boot.autoconfigure.cache.CaffeineCacheConfiguration"
8 = "org.springframework.boot.autoconfigure.cache.SimpleCacheConfiguration"
9 = "org.springframework.boot.autoconfigure.cache.NoOpCacheConfiguration"
*/
- 如果没有引
Redis
, 则SimpleCacheConfiguration
这个就是默认的配置类 - 在
SimpleCacheConfiguration
注入了一个ConcurrentMapCacheManager
-
ConcurrentMapCacheManager
实现了CacheManager
接口 -
ConcurrentMapCacheManager
通过ConcurrentHashMap
把数据缓存起来 - 在
CacheManager
有一个Cache getCache(String var1)
方法换取缓存 - 流程大概就这里,感兴趣的同学可以打断点阅读源码
本章代码示例地址
- Github: https://github.com/rstyro/Springboot/tree/master/SpringBoot-RedisCacheManager
- Gitee : https://gitee.com/rstyro/spring-boot/tree/master/SpringBoot-RedisCacheManager