Map作为缓存使用

 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;
         }
     }
 }

转载处：https://blog.csdn.net/xsj_blog/article/details/83056143