轻量级redis缓存追加

本次主要改动范围：
1.分类列表缓存
2.标签列表缓存

追加的新类库
1.redis
2.jsr310→java8时间类localdatetime无法解析的问题
3.jaskson-hibernate6->hibernate 字段懒加载问题

其他改动
1.修改了初始化脚本的用户名，追加密码说明

backend/src/main/java/com/openisle/config/CachingConfig.java

@@ -0,0 +1,109 @@
+package com.openisle.config;
+
+import com.fasterxml.jackson.annotation.JsonAutoDetect;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.annotation.PropertyAccessor;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.jsontype.impl.LaissezFaireSubTypeValidator;
+import com.fasterxml.jackson.datatype.hibernate6.Hibernate6Module;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import org.springframework.cache.CacheManager;
+import org.springframework.cache.annotation.EnableCaching;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Primary;
+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.GenericJackson2JsonRedisSerializer;
+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;
+
+/**
+ * Redis 缓存配置类
+ * @author smallclover
+ * @since 2025-09-04
+ */
+@Configuration
+@EnableCaching
+public class CachingConfig {
+
+    // 标签缓存名
+    public static final String TAG_CACHE_NAME="openisle_tags";
+    // 分类缓存名
+    public static final String CATEGORY_CACHE_NAME="openisle_categories";
+
+    /**
+     * 自定义Redis的序列化器
+     * @return
+     */
+    @Bean()
+    @Primary
+    public RedisSerializer<Object> redisSerializer() {
+        // 注册 JavaTimeModule 來支持 Java 8 的日期和时间 API,否则回报一下错误，同时还要引入jsr310
+
+        // org.springframework.data.redis.serializer.SerializationException: Could not write JSON: Java 8 date/time type `java.time.LocalDateTime` not supported by default:
+        // add Module "com.fasterxml.jackson.datatype:jackson-datatype-jsr310" to enable handling
+        // (through reference chain: java.util.ArrayList[0]->com.openisle.dto.TagDto["createdAt"])
+        // 设置可见性，允许序列化所有元素
+        ObjectMapper objectMapper = new ObjectMapper();
+        objectMapper.registerModule(new JavaTimeModule());
+        // Hibernate6Module 可以自动处理懒加载代理对象。
+        // Tag对象的creator是FetchType.LAZY
+        objectMapper.registerModule(new Hibernate6Module()
+                .disable(Hibernate6Module.Feature.USE_TRANSIENT_ANNOTATION));
+        // service的时候带上类型信息
+        // 启用类型信息，避免 LinkedHashMap 问题
+        objectMapper.activateDefaultTyping(
+                LaissezFaireSubTypeValidator.instance,
+                ObjectMapper.DefaultTyping.NON_FINAL,
+                JsonTypeInfo.As.PROPERTY
+        );
+        objectMapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.ANY);
+        return new GenericJackson2JsonRedisSerializer(objectMapper);
+    }
+
+    /**
+     * 配置 Spring Cache 使用 RedisCacheManager
+     */
+    @Bean
+    public CacheManager cacheManager(RedisConnectionFactory connectionFactory, RedisSerializer<Object> redisSerializer) {
+
+        RedisCacheConfiguration config = RedisCacheConfiguration.defaultCacheConfig()
+                .entryTtl(Duration.ZERO) // 默认缓存不过期
+                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(new StringRedisSerializer()))
+                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(redisSerializer))
+                .disableCachingNullValues(); // 禁止缓存 null 值
+//        个别缓存单独设置TTL时间
+//        Map<String, RedisCacheConfiguration> cacheConfigs = new HashMap<>();
+//        cacheConfigs.put("openisle_tags", RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ZERO));
+//        cacheConfigs.put("openisle_categories", RedisCacheConfiguration.defaultCacheConfig().entryTtl(Duration.ZERO));
+
+        return RedisCacheManager.builder(connectionFactory)
+                .cacheDefaults(config)
+                .build();
+    }
+
+    /**
+     * 配置 RedisTemplate，支持直接操作 Redis
+     */
+    @Bean
+    public RedisTemplate<String, Object> redisTemplate(RedisConnectionFactory connectionFactory,  RedisSerializer<Object> redisSerializer) {
+        RedisTemplate<String, Object> template = new RedisTemplate<>();
+        template.setConnectionFactory(connectionFactory);
+
+        // key 和 hashKey 使用 String 序列化
+        template.setKeySerializer(new StringRedisSerializer());
+        template.setHashKeySerializer(new StringRedisSerializer());
+
+        // value 和 hashValue 使用 JSON 序列化
+        template.setValueSerializer(redisSerializer);
+        template.setHashValueSerializer(redisSerializer);
+
+        return template;
+    }
+}