Map 缓存实现

怼烎@ 2021-09-16 15:24 355阅读 0赞

package xxx.xxx.xxx;
    
    import java.util.Map;
    import java.util.concurrent.ConcurrentHashMap;
    
    /**
     * Map 缓存实现
     */
    public class MapCache {
    
        /**
         * 默认存储1024个缓存
         */
        private static final int DEFAULT_CACHES = 1024;
    
        private static final MapCache INS = new MapCache();
    
        public static MapCache single() {
            return INS;
        }
    
        /**
         * 缓存容器
         */
        private Map<String, CacheObject> cachePool;
    
        public MapCache() {
            this(DEFAULT_CACHES);
        }
    
        public MapCache(int cacheCount) {
            cachePool = new ConcurrentHashMap<>(cacheCount);
        }
    
        /**
         * 读取一个缓存
         *
         * @param key 缓存key
         * @param <T>
         * @return
         */
        public <T> T get(String key) {
            CacheObject cacheObject = cachePool.get(key);
            if (null != cacheObject) {
                long cur = System.currentTimeMillis() / 1000;
                if (cacheObject.getExpired() <= 0 || cacheObject.getExpired() > cur) {
                    Object result = cacheObject.getValue();
                    return (T) result;
                }
            }
            return null;
        }
    
        /**
         * 读取一个hash类型缓存
         *
         * @param key   缓存key
         * @param field 缓存field
         * @param <T>
         * @return
         */
        public <T> T hget(String key, String field) {
            key = key + ":" + field;
            return this.get(key);
        }
    
        /**
         * 设置一个缓存
         *
         * @param key   缓存key
         * @param value 缓存value
         */
        public void set(String key, Object value) {
            this.set(key, value, -1);
        }
    
        /**
         * 设置一个缓存并带过期时间
         *
         * @param key     缓存key
         * @param value   缓存value
         * @param expired 过期时间，单位为秒
         */
        public void set(String key, Object value, long expired) {
            expired = expired > 0 ? System.currentTimeMillis() / 1000 + expired : expired;
            CacheObject cacheObject = new CacheObject(key, value, expired);
            cachePool.put(key, cacheObject);
        }
    
        /**
         * 设置一个hash缓存
         *
         * @param key   缓存key
         * @param field 缓存field
         * @param value 缓存value
         */
        public void hset(String key, String field, Object value) {
            this.hset(key, field, value, -1);
        }
    
        /**
         * 设置一个hash缓存并带过期时间
         *
         * @param key     缓存key
         * @param field   缓存field
         * @param value   缓存value
         * @param expired 过期时间，单位为秒
         */
        public void hset(String key, String field, Object value, long expired) {
            key = key + ":" + field;
            expired = expired > 0 ? System.currentTimeMillis() / 1000 + expired : expired;
            CacheObject cacheObject = new CacheObject(key, value, expired);
            cachePool.put(key, cacheObject);
        }
    
        /**
         * 根据key删除缓存
         *
         * @param key 缓存key
         */
        public void del(String key) {
            cachePool.remove(key);
        }
    
        /**
         * 根据key和field删除缓存
         *
         * @param key   缓存key
         * @param field 缓存field
         */
        public void hdel(String key, String field) {
            key = key + ":" + field;
            this.del(key);
        }
    
        /**
         * 清空缓存
         */
        public void clean() {
            cachePool.clear();
        }
    
        static class CacheObject {
            private String key;
            private Object value;
            private long expired;
    
            public CacheObject(String key, Object value, long expired) {
                this.key = key;
                this.value = value;
                this.expired = expired;
            }
    
            public String getKey() {
                return key;
            }
    
            public Object getValue() {
                return value;
            }
    
            public long getExpired() {
                return expired;
            }
        }
    }