实现 MyBatis Cache 接口，用于自定义缓存为 Redis

末蓝、 2021-07-25 21:06 349阅读 0赞

package com.funtl.itoken.common.utils;
    
    import com.funtl.itoken.common.context.ApplicationContextHolder;
    import org.apache.ibatis.cache.Cache;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.data.redis.core.RedisCallback;
    import org.springframework.data.redis.core.RedisTemplate;
    import org.springframework.data.redis.core.ValueOperations;
    
    import java.util.concurrent.TimeUnit;
    import java.util.concurrent.locks.ReadWriteLock;
    import java.util.concurrent.locks.ReentrantReadWriteLock;
    
    /**
     * Redis 缓存工具类
     * <p>Title: RedisCache</p>
     * <p>Description: </p>
     *
     * @author Lusifer
     * @version 1.0.0
     * @date 2018/8/13 6:03
     */
    public class RedisCache implements Cache {
        private static final Logger logger = LoggerFactory.getLogger(RedisCache.class);
    
        private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();
        private final String id; // cache instance id
        private RedisTemplate redisTemplate;
    
        private static final long EXPIRE_TIME_IN_MINUTES = 30; // redis过期时间
    
        public RedisCache(String id) {
            if (id == null) {
                throw new IllegalArgumentException("Cache instances require an ID");
            }
            this.id = id;
        }
    
        @Override
        public String getId() {
            return id;
        }
    
        /**
         * Put query result to redis
         *
         * @param key
         * @param value
         */
        @Override
        public void putObject(Object key, Object value) {
            try {
                RedisTemplate redisTemplate = getRedisTemplate();
                ValueOperations opsForValue = redisTemplate.opsForValue();
                opsForValue.set(key, value, EXPIRE_TIME_IN_MINUTES, TimeUnit.MINUTES);
                logger.debug("Put query result to redis");
            } catch (Throwable t) {
                logger.error("Redis put failed", t);
            }
        }
    
        /**
         * Get cached query result from redis
         *
         * @param key
         * @return
         */
        @Override
        public Object getObject(Object key) {
            try {
                RedisTemplate redisTemplate = getRedisTemplate();
                ValueOperations opsForValue = redisTemplate.opsForValue();
                logger.debug("Get cached query result from redis");
    //            System.out.println("****" + opsForValue.get(key).toString());
                return opsForValue.get(key);
            } catch (Throwable t) {
                logger.error("Redis get failed, fail over to db", t);
                return null;
            }
        }
    
        /**
         * Remove cached query result from redis
         *
         * @param key
         * @return
         */
        @Override
        @SuppressWarnings("unchecked")
        public Object removeObject(Object key) {
            try {
                RedisTemplate redisTemplate = getRedisTemplate();
                redisTemplate.delete(key);
                logger.debug("Remove cached query result from redis");
            } catch (Throwable t) {
                logger.error("Redis remove failed", t);
            }
            return null;
        }
    
        /**
         * Clears this cache instance
         */
        @Override
        public void clear() {
            RedisTemplate redisTemplate = getRedisTemplate();
            redisTemplate.execute((RedisCallback) connection -> {
                connection.flushDb();
                return null;
            });
            logger.debug("Clear all the cached query result from redis");
        }
    
        /**
         * This method is not used
         *
         * @return
         */
        @Override
        public int getSize() {
            return 0;
        }
    
        @Override
        public ReadWriteLock getReadWriteLock() {
            return readWriteLock;
        }
    
        private RedisTemplate getRedisTemplate() {
            if (redisTemplate == null) {
                redisTemplate = ApplicationContextHolder.getBean("redisTemplate");
            }
            return redisTemplate;
        }
    }