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 static 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 static <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 static void set(String key, Object value) {

         INS.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 static 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;

         }

     }

 }