配置spring cache RedisCacheManager的序列化方法

通過查看autoconfigure源碼

org.springframework.boot.autoconfigure.cache.RedisCacheConfiguration;

部分源碼如下：

private org.springframework.data.redis.cache.RedisCacheConfiguration determineConfiguration(
      ClassLoader classLoader) {
   if (this.redisCacheConfiguration != null) {
      return this.redisCacheConfiguration;
   }
   Redis redisProperties = this.cacheProperties.getRedis();
   org.springframework.data.redis.cache.RedisCacheConfiguration config = org.springframework.data.redis.cache.RedisCacheConfiguration
         .defaultCacheConfig();
   config = config.serializeValuesWith(SerializationPair
         .fromSerializer(new JdkSerializationRedisSerializer(classLoader)));
   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;
}

可以看到默認是使用的 JdkSerializationRedisSerializer ，還有就是如果容器里已經有 redisCacheConfiguration 就直接使用了。

那么只需要自己注入一個 RedisCacheConfiguration 即可。

代碼可以直接用源碼里面的：)，調整序列化部分即可。

@Configuration
@Conditional(SimpleCacheCondition.class)
public class MyRedisCacheConfiguration {
    private final CacheProperties cacheProperties;
    MyRedisCacheConfiguration(CacheProperties cacheProperties) {
        this.cacheProperties = cacheProperties;
    }
    @Bean
    public org.springframework.data.redis.cache.RedisCacheConfiguration determineConfiguration() {
        CacheProperties.Redis redisProperties = this.cacheProperties.getRedis();
        org.springframework.data.redis.cache.RedisCacheConfiguration config = org.springframework.data.redis.cache.RedisCacheConfiguration
                .defaultCacheConfig();
        config = config.serializeValuesWith(RedisSerializationContext.SerializationPair
                .fromSerializer(valueSerializer()));
        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;
    }
    /**
     * 使用Jackson序列化器
     * @return
     */
    private RedisSerializer<Object> valueSerializer() {
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
        objectMapper.enableDefaultTyping(ObjectMapper.DefaultTyping.NON_FINAL);
        return new GenericJackson2JsonRedisSerializer(objectMapper);
    }

}

這里使用的是 GenericJackson2JsonRedisSerializer ；

參考文檔：

https://docs.spring.io/spring-data/redis/docs/current/api/org/springframework/data/redis/serializer/RedisSerializer.html

可以看到已有的可用序列化器:

GenericJackson2JsonRedisSerializer, GenericToStringSerializer, Jackson2JsonRedisSerializer, JdkSerializationRedisSerializer, OxmSerializer, StringRedisSerializer

這里順便學習一下 @Conditional ，這個注解可以幫我們控制什么時候來注冊組件。

比如這里寫了一個 RedisCacheConfiguration 配置，那我只想在啟用了redis緩存時再注冊，就可以使用這個注解，如 @Conditional(SimpleCacheCondition.class) 。

定義 SimpleCacheCondition ，部分代碼參考 org.springframework.boot.autoconfigure.cache.CacheCondition 

public class SimpleCacheCondition implements Condition {

    /**
     * Determine if the condition matches.
     *
     * @param context  the condition context
     * @param metadata metadata of the {@link AnnotationMetadata class}
     *                 or {@link MethodMetadata method} being checked
     * @return {@code true} if the condition matches and the component can be registered,
     * or {@code false} to veto the annotated component's registration
     */
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        try {
            String sourceClass = "";
            if (metadata instanceof ClassMetadata) {
                sourceClass = ((ClassMetadata) metadata).getClassName();
            }
            Environment environment = context.getEnvironment();
            BindResult<CacheType> specified = Binder.get(environment)
                    .bind("spring.cache.type", CacheType.class);
            if (!specified.isBound()) {
                return false;
            }
　　　　　　　//redis cache 啟用 並且 是自定義的redisCacheConfiguration
            if (specified.get().equals(CacheType.REDIS) && sourceClass.equals(MyRedisCacheConfiguration.class.getTypeName())) {
                return true;
            }
        }catch (Exception ex)
        {}
        return false;
    }
}