三十四、Springboot集成SpringCache + Redis，实现缓存

  Springboot集成SpringCache + Redis，以利用SpringCache的注解和Redis的存储、过期等。

（一）自定义缓存配置文件

@Configuration
public class CacheConfiguration {
    /**
     * 搜索小说缓存
     */
    public static final String BOOKS_SEARCH_CACHE = "books_search";
    /**
     * 章节内容缓存
     */
    public static final String CHAPTERS_BOOK_CACHE = "chapters_book";
    /**
     * 章节内容缓存
     */
    public static final String CHAPTER_CONTENT_CACHE = "chapter_content";

    @Primary
    @Bean
    public CacheManager cacheManager(RedisConnectionFactory redisConnectionFactory){
        RedisCacheConfiguration redisCacheConfiguration = RedisCacheConfiguration.defaultCacheConfig();
        redisCacheConfiguration = redisCacheConfiguration
                //设置缓存的默认超时时间：30分钟
                .entryTtl(Duration.ofMinutes(30L))
                //如果是空值，不缓存
                .disableCachingNullValues()
                //设置key序列化器
                .serializeKeysWith(RedisSerializationContext.SerializationPair.fromSerializer(keySerializer()))
                //设置value序列化器
                .serializeValuesWith(RedisSerializationContext.SerializationPair.fromSerializer(valueSerializer()));
        return RedisCacheManager
                .builder(RedisCacheWriter.nonLockingRedisCacheWriter(redisConnectionFactory))
                .cacheDefaults(redisCacheConfiguration)
                .build();
    }

    /**
     * key序列化器
     */
    private RedisSerializer<String> keySerializer() {
        return new StringRedisSerializer();
    }
    /**
     * value序列化器
     */
    private RedisSerializer<Object> valueSerializer() {
        return new GenericJackson2JsonRedisSerializer();
    }
}

（二）开启缓存
@EnableCaching：开启缓存

@SpringBootApplication
@ServletComponentScan
@MapperScan("com.yuedu.dao")
@EnableScheduling
@EnableCaching
public class YueduApplication {

  public static void main(String[] args) {
    SpringApplication.run(YueduApplication.class, args);
  }

}

（三）应用

@Cacheable(cacheNames = CacheConfiguration.CHAPTERS_BOOK_CACHE, key = "#root.methodName+'['+#bookId+']'")
    public List<Chapter> searchChaptersByBookId(Integer bookId, int start, int size) {
        if (bookId == null || bookId < 1){
            throw new BaseException(ResultEnum.PARAM_ERROR);
        }
        Chapter chapter = new Chapter();
        chapter.setBookId(bookId);
        //设置分页
        PageHelper.startPage(start, size);
        return selectChapters(chapter);
    }