SpringBoot 和SpringCloud 使用redis 进行数据缓存基本讲解

 //spring boot 怎么使用redis
    //1. 引入 redis 依赖
//      <!-- redis -->
//        <dependency>
//            <groupId>org.springframework.boot</groupId>
//            <artifactId>spring-boot-starter-data-redis</artifactId>
//        </dependency>
//
//        <!-- spring2.X集成redis所需common-pool2-->
//        <dependency>
//            <groupId>org.apache.commons</groupId>
//            <artifactId>commons-pool2</artifactId>
//            <version>2.6.0</version>
//        </dependency>

    //2. 创建配置类  配置类文件 固定 写法

package com.school.service_base;

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.RedisConnectionFactory;
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 java.time.Duration;

/**
 * @User: Json
 * @Date: 2021/12/21
 * 固定写法
 **/
@EnableCaching  //开启缓存
@Configuration//配置类
public class RedisConfig extends CachingConfigurerSupport {
    @Bean
    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
        RedisTemplate<String, Object> template = new RedisTemplate<>();
        RedisSerializer<String> redisSerializer = new StringRedisSerializer();
        Jackson2JsonRedisSerializer jackson2JsonRedisSerializer = new Jackson2JsonRedisSerializer(Object.class);
        ObjectMapper om = new ObjectMapper();
        om.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        om.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        jackson2JsonRedisSerializer.setObjectMapper(om);
        template.setConnectionFactory(factory);
        //key序列化方式
        template.setKeySerializer(redisSerializer);
        //value序列化
        template.setValueSerializer(jackson2JsonRedisSerializer);
        //value hashmap序列化
        template.setHashValueSerializer(jackson2JsonRedisSerializer);
        return template;
    }

    @Bean
    public CacheManager cacheManager(RedisConnectionFactory factory) {
        RedisSerializer<String> 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）,过期时间600秒
        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
                .entryTtl(Duration.ofSeconds(600))
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(jackson2JsonRedisSerializer))
                .disableCachingNullValues();
        RedisCacheManager cacheManager = RedisCacheManager.builder(factory)
                .cacheDefaults(config)
                .build();
        return cacheManager;
    }

}


    //3. 在配置文件中配置 redis 参数
//    spring.redis.host=127.0.0.1
//    spring.redis.port=6379
//    spring.redis.database=0
//    spring.redis.timeout=1800000

    //4. 使用
    //   @Cacheable  当缓存里有 直接去取  如果没有 去查询 然后再放到缓存里 一般用于查询 用的多
    //   @CachePut   每次都会执行 并将起结果存入指定缓存中  一般用于新增
    //   @CacheEvict  有个参数 会清空指定缓存  一般用于 更新或者删除方法  一般多