SpringCache缓存自定义配置的实现

2024-04-02 19:04:59 811人浏览八月长安

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摘要

目录1.key的名字和TTL时间2.缓存数据保存为JSON格式3.使用缓存前缀4.缓存null，防止缓存穿透Cacheable指定自定义属性详情请参考spring官网添加链接描述

1.key的名字和TTL时间

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@Cacheable(value = {"cateGory"},key ="'TopCategorys'" )
@Override
public List<CategoryEntity> getTopCategorys() {
    System.out.println(".....getTopCategorys..........");
    long startTime = System.currentTimeMillis();
    List<CategoryEntity> categoryEntityList = this.baseMapper.selectList(
            new QueryWrapper<CategoryEntity>().eq("parent_cid", 0));
    System.out.println("消耗时间:" + (System.currentTimeMillis() - startTime));
    return categoryEntityList;
}

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   // @Cacheable(value = {"category"},key ="'TopCategorys'" )
    @Cacheable(value = {"category"},key ="#root.method.name" )
    @Override
    public List<CategoryEntity> getTopCategorys() {
        System.out.println(".....getTopCategorys..........");
        long startTime = System.currentTimeMillis();
        List<CategoryEntity> categoryEntityList = this.baseMapper.selectList(
                new QueryWrapper<CategoryEntity>().eq("parent_cid", 0));
        System.out.println("消耗时间:" + (System.currentTimeMillis() - startTime));
        return categoryEntityList;
    }

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2.缓存数据保存为json格式

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* 原理:
* CacheAutoConfiguration(selectImports方法)--->CacheConfigurations(MAPPINGS)
* --->RedisCacheConfiguration-->cacheManager方法--->RedisCacheManager初始化所有的缓存(determineConfiguration方法
* 每个缓存决定使用什么配置) --->createConfiguration方法

在config包下新建MyCacheConfig配置类

package com.atguigu.gulimall.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;


@EnableCaching
@Configuration
public class MyCacheConfig {

    @Bean
    RedisCacheConfiguration redisCacheConfiguration(){
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig();
        // config = config.entryTtl();
        config = config.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()));
        config = config.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer()));
        return config;
    }
}

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发现ttl变成了-1,我们的application.properties没起作用

package com.atguigu.gulimall.product.config;

import org.springframework.boot.autoconfigure.cache.CacheProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
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;


@EnableConfigurationProperties(CacheProperties.class)
@EnableCaching
@Configuration
public class MyCacheConfig {

    @Bean
    RedisCacheConfiguration redisCacheConfiguration(CacheProperties cacheProperties){
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig();
        // config = config.entryTtl();
        config = config.serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()));
        config = config.serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(new GenericJackson2JsonRedisSerializer()));

        CacheProperties.Redis redisProperties = cacheProperties.getRedis();
        //将配置文件中所有的配置都生效
        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;
    }
}

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3.使用缓存前缀

在application.properties文件中

spring.cache.type=redis

#spring.cache.cache-names=qq
#TTL 毫秒为单位
spring.cache.redis.time-to-live=3600000

#如果指定了前缀就用我们指定的前缀，如果没有就默认使用缓存的名字作为前缀
spring.cache.redis.key-prefix=CACHE_
spring.cache.redis.use-key-prefix=true

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4.缓存null，防止缓存穿透

在application.properties文件中

spring.cache.type=redis

#spring.cache.cache-names=qq
#TTL 毫秒为单位
spring.cache.redis.time-to-live=3600000

#如果指定了前缀就用我们指定的前缀，如果没有就默认使用缓存的名字作为前缀
spring.cache.redis.key-prefix=CACHE_
spring.cache.redis.use-key-prefix=true

#是否缓存空值，防止缓存穿透
spring.cache.redis.cache-null-values=true

代码中直接返回null

  
   // @Cacheable(value = {"category"},key ="'TopCategorys'" )
    @Cacheable(value = {"category"},key ="#root.method.name" )
    @Override
    public List<CategoryEntity> getTopCategorys() {
        System.out.println(".....getTopCategorys..........");
        long startTime = System.currentTimeMillis();
        List<CategoryEntity> categoryEntityList = this.baseMapper.selectList(
                new QueryWrapper<CategoryEntity>().eq("parent_cid", 0));
        System.out.println("消耗时间:" + (System.currentTimeMillis() - startTime));
//        return categoryEntityList;
        return null;
    }

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