SpringBoot用注解实现redis缓存

冷不防 2023-09-27 09:48 107阅读 0赞

## 1.入口类加注解 @EnableCaching ##

@EnableRetry    //重试
    @SpringBootApplication
    @MapperScan("cn.my.dao")
    @EnableCaching      //开启redis缓存
    @EnableScheduling   //开启定时注解
    @EnableAsync        //异步
    public class MyApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(MyApplication.class, args);
    
        }

## 2.redis缓存的配置文件 ##

package cn.my.config.redis;
    
    import com.fasterxml.jackson.annotation.JsonAutoDetect;
    import com.fasterxml.jackson.annotation.PropertyAccessor;
    import com.fasterxml.jackson.databind.ObjectMapper;
    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.cache.RedisCacheWriter;
    import org.springframework.data.redis.connection.RedisConnectionFactory;
    import org.springframework.data.redis.core.RedisTemplate;
    import org.springframework.data.redis.listener.RedisMessageListenerContainer;
    import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
    import org.springframework.data.redis.serializer.RedisSerializationContext;
    import org.springframework.data.redis.serializer.StringRedisSerializer;
    
    import java.time.Duration;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.Random;
    
    /**
     *  关于redis缓存的配置
     * @Description 配置redis（spring boot默认实现了redis配置，但是实现的是RedisTemplate<Object, Object>，
     *                      为了便于写代码重新配置为RedisTemplate<Object, Object>）
     *
     **/
    @Configuration
    @EnableCaching
    public class RedisCacheConfig{
    
        private Integer time = new Random().nextInt(60*60*10);
    
        @Bean
        public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory factory) {
    
            RedisTemplate<String, Object> template = new RedisTemplate<String, Object>();
            template.setConnectionFactory(factory);
            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);
            StringRedisSerializer stringRedisSerializer = new StringRedisSerializer();
            // key采用String的序列化方式
            template.setKeySerializer(stringRedisSerializer);
            // hash的key也采用String的序列化方式
            template.setHashKeySerializer(stringRedisSerializer);
            // value序列化方式采用jackson
            template.setValueSerializer(jackson2JsonRedisSerializer);
            // hash的value序列化方式采用jackson
            template.setHashValueSerializer(jackson2JsonRedisSerializer);
            template.afterPropertiesSet();
            return template;
        }
    
        @Bean
        RedisMessageListenerContainer container(RedisConnectionFactory connectionFactory) {
            RedisMessageListenerContainer container = new RedisMessageListenerContainer();
            container.setConnectionFactory(connectionFactory);
            return container;
        }
    
        //从这往下是配置@cache失效时间
        @Bean
        public RedisCacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {
            return new RedisCacheManager(
                    RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory),
                    this.getRedisCacheConfigurationWithTtl(time), // 默认策略，未配置的 key 会使用这个
                    this.getRedisCacheConfigurationMap() // 指定 key 策略
            );
        }
    
        private Map<String, RedisCacheConfiguration> getRedisCacheConfigurationMap() {
            Map<String, RedisCacheConfiguration> redisCacheConfigurationMap = new HashMap<>();
    
            //自定义设置缓存时间
            redisCacheConfigurationMap.put("goodsCompCache", this.getRedisCacheConfigurationWithTtl(60*60));
    
            return redisCacheConfigurationMap;
        }
    
        private RedisCacheConfiguration getRedisCacheConfigurationWithTtl(Integer seconds) {
            Jackson2JsonRedisSerializer<Object> 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);
            RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig();
            redisCacheConfiguration = redisCacheConfiguration.serializeValuesWith(
                    RedisSerializationContext
                            .SerializationPair
                            .fromSerializer(jackson2JsonRedisSerializer)
            ).entryTtl(Duration.ofSeconds(seconds));
    
            return redisCacheConfiguration;
        }
    }

## 3.service 添加redis缓存注解 ##

*      @CachePut(value = "tickets")

> 每次查询都会查询数据库

*      @Cacheable(value = "ticketById", key = "#id")

> 缓存中有就不查数据库

*  @CacheEvict(value = "ticketById", key = "\#id")

> 更新操作