LangChain的缓存机制如何工作？如何优化性能

// InMemoryCache的核心逻辑
publicclassInMemoryCache{
    privatefinalMap<String,CacheEntry> cacheMap =newConcurrentHashMap<>();

    publicStringgetCachedResponse(String prompt){
        String cacheKey =generateHashKey(prompt);
        CacheEntry entry = cacheMap.get(cacheKey);

        if(entry !=null&&!entry.isExpired()){
            return entry.getResponse();
        }
        returnnull;
    }

    publicvoidputCache(String prompt,String response,Duration ttl){
        String cacheKey =generateHashKey(prompt);
        CacheEntry entry =newCacheEntry(response,System.currentTimeMillis()+ ttl.toMillis());
        cacheMap.put(cacheKey, entry);
    }

    privateStringgenerateHashKey(String prompt){
        returnDigestUtils.md5Hex(prompt);
    }
}

publicclassSemanticCache{
    privatefinalVectorDatabase vectorDb;
    privatefinalEmbeddingService embeddingService;
    privatefinaldouble similarityThreshold;

    publicSemanticCache(VectorDatabase vectorDb,EmbeddingService embeddingService){
        this.vectorDb = vectorDb;
        this.embeddingService = embeddingService;
        this.similarityThreshold =0.85;
    }

    publicStringfindSimilarResponse(String query){
        Vector queryVector = embeddingService.embed(query);
        List<SimilarResult> similarResults = vectorDb.searchSimilar(queryVector, similarityThreshold,5);

        if(!similarResults.isEmpty()){
            return similarResults.get(0).getResponse();
        }
        returnnull;
    }

    publicvoidstoreQuery(String query,String response){
        Vector queryVector = embeddingService.embed(query);
        CacheEntry entry =newCacheEntry(query, response, queryVector,System.currentTimeMillis());
        vectorDb.store(entry);
    }
}

// Redis缓存配置示例
@Configuration
publicclassCacheConfig{

    @Bean
    publicRedisTemplate<String,Object>redisTemplate(){
        RedisTemplate<String,Object> template =newRedisTemplate<>();

        // 连接池配置
        JedisPoolConfig poolConfig =newJedisPoolConfig();
        poolConfig.setMaxTotal(200);
        poolConfig.setMaxIdle(160);
        poolConfig.setMinIdle(50);
        poolConfig.setTestOnBorrow(true);

        JedisConnectionFactory factory =newJedisConnectionFactory(poolConfig);
        template.setConnectionFactory(factory);

        // 序列化配置
        template.setKeySerializer(newStringRedisSerializer());
        template.setValueSerializer(newGenericJackson2JsonRedisSerializer());

        return template;
    }

    @Bean
    publicCacheManagercacheManager(){
        RedisCacheManager.Builder builder =RedisCacheManager
        .RedisCacheManagerBuilder
        .fromConnectionFactory(redisConnectionFactory())
        .cacheDefaults(cacheConfiguration(Duration.ofHours(12)));

        return builder.build();
    }
}