缓存一致性

锁
设置过期时间

读写锁
设置过期时间

Spring Cache

1.读模式
缓存穿透：查询一个null数据，解决：开启缓存空数据，spring.cache.redis.cache-null-values=true
缓存击穿：大量并发进来查询一个正好过期的数据，解决：加锁
缓存雪崩：大量的key同时过期 解决：加过期时间，spring.cache.redis.time-to-live=3600000
2.写模式：缓存与数据库一致
读写加锁。
引入Canal，感知到MySQL的更新去更新数据库
读多写多，直接去数据库查询就行

pom.xml

        <!-- https://mvnrepository.com/artifact/org.springframework.session/spring-session-data-redis --><dependency><groupId>org.springframework.session</groupId><artifactId>spring-session-data-redis</artifactId></dependency><!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-cache --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-cache</artifactId></dependency>

application.yml

spring:cache:type: redisredis:time-to-live: 3600000cache-null-values: true

CubemallProductApplication.java

package com.xd.cubemall.product;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;@EnableCaching
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients(basePackages = "com.xd.cubemall.product.feign")
public class CubemallProductApplication {public static void main(String[] args) {SpringApplication.run(CubemallProductApplication.class, args);}}

SpringCache改造三级分类

    /*** 使用SpringCache改造三级分类* @return*/@Cacheable(value={"category"}, key = "#root.method.name")public List<CategoryVo> getLevel1Categorys() {System.out.println("缓存不命中，查询数据库。。。");//2.缓存中没有数据，查询数据库，从数据库查询分类数据List<CategoryVo> categoryJsonFromDb = getCategoryJsonFromWithRedissonLock();return categoryJsonFromDb;}

MyCacheConfig.java

package com.xd.cubemall.product.config;import org.springframework.boot.autoconfigure.cache.CacheProperties;
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.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.RedisSerializationContext;
import org.springframework.data.redis.serializer.StringRedisSerializer;@Configuration
@EnableCaching
public class MyCacheConfig {@BeanRedisCacheConfiguration redisCacheConfiguration(CacheProperties cacheProperties){RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig();//修改key和value的序列号机制config = config.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()));config = config.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer()));//将配置文件中的所有配置进行生效CacheProperties.Redis redisProperties = cacheProperties.getRedis();if (redisProperties.getTimeToLive() != null) {config = config.entryTtl(redisProperties.getTimeToLive());}if (redisProperties.getKeyPrefix() != null) {config = config.prefixKeysWith(redisProperties.getKeyPrefix());}if (!redisProperties.isCacheNullValues()) {config = config.disableCachingNullValues();}if (!redisProperties.isUseKeyPrefix()) {config = config.disableKeyPrefix();}return config;}
}

缓存一致性

    /*** 三级菜单的级联更新 (缓存一致性)* @param category*/@CacheEvict(value = "category", key = "'getLevel1Categorys'")@Overridepublic void updateCascade(CategoryEntity category) {this.updateById(category);}