🐛 Fix: Redis 캐시 postList 역직렬화 타입 이슈 해결

Author: 안훈기

src/main/java/com/be/sportizebe/global/config/RedisCacheConfig.java

@@ -1,10 +1,9 @@
 package com.be.sportizebe.global.config;
 
-import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.be.sportizebe.domain.post.dto.response.PostPageResponse;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.databind.SerializationFeature;
 import com.fasterxml.jackson.databind.json.JsonMapper;
-import com.fasterxml.jackson.databind.jsontype.impl.LaissezFaireSubTypeValidator;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 import org.springframework.cache.CacheManager;
 import org.springframework.cache.annotation.EnableCaching;
@@ -13,9 +12,8 @@
 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.serializer.GenericJackson2JsonRedisSerializer;
+import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
 import org.springframework.data.redis.serializer.RedisSerializationContext;
-import org.springframework.data.redis.serializer.RedisSerializer;
 
 import java.time.Duration;
 import java.util.HashMap;
@@ -27,30 +25,35 @@ public class RedisCacheConfig {
 
     @Bean
     public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {
-
+        // 캐시 역직렬화를 위해 타입 정보(@class)를 포함하도록 설정
         ObjectMapper objectMapper = JsonMapper.builder()
                 .addModule(new JavaTimeModule())
                 .disable(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS)
+                // ❗ 타입 정보 절대 쓰지 않음
                 .build();
-        objectMapper.activateDefaultTyping(
-                LaissezFaireSubTypeValidator.instance,
-                ObjectMapper.DefaultTyping.NON_FINAL,
-                JsonTypeInfo.As.PROPERTY
-        );
         // 캐시에 들어가는 값의 직렬화 방식 결정
-        RedisSerializer<Object> valueSerializer =
-                new GenericJackson2JsonRedisSerializer(objectMapper);
+
+        // 기본 캐시(대부분)는 Object로 직렬화/역직렬화
+        Jackson2JsonRedisSerializer<Object> defaultValueSerializer =
+                new Jackson2JsonRedisSerializer<>(Object.class);
+        defaultValueSerializer.setObjectMapper(objectMapper);
+
+        // postList 캐시는 PostPageResponse 타입으로 역직렬화되어야 ClassCastException이 나지 않음
+        Jackson2JsonRedisSerializer<PostPageResponse> postListValueSerializer =
+                new Jackson2JsonRedisSerializer<>(PostPageResponse.class);
+        postListValueSerializer.setObjectMapper(objectMapper);
         // TTL(캐시 수명) 정책 정의
         // 아무 설정 없는 캐시(Default) = 5분
         RedisCacheConfiguration defaultConfig =
                 RedisCacheConfiguration.defaultCacheConfig()
                         .serializeValuesWith(
-                                RedisSerializationContext.SerializationPair.fromSerializer(valueSerializer)
+                                RedisSerializationContext.SerializationPair.fromSerializer(defaultValueSerializer)
                         )
                         .entryTtl(Duration.ofMinutes(5));
 
         Map<String, RedisCacheConfiguration> cacheConfigs = new HashMap<>();
 
+
         // 캐시별로 TTL override 가능 ( post, commet 등 우리가 원하는 값으로 TTL 설정 가능 )
         cacheConfigs.put(
                 "facilityNear",
@@ -62,7 +65,11 @@ public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory)
         );
         cacheConfigs.put(
                 "postList",
-                defaultConfig.entryTtl(Duration.ofSeconds(30))
+                RedisCacheConfiguration.defaultCacheConfig()
+                        .serializeValuesWith(
+                                RedisSerializationContext.SerializationPair.fromSerializer(postListValueSerializer)
+                        )
+                        .entryTtl(Duration.ofSeconds(30))
         );
         return RedisCacheManager.builder(redisConnectionFactory)
                 .cacheDefaults(defaultConfig)