基于LinkedHashMap的线程安全化LRU Cache缓存

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import java.util.LinkedHashMap; import java.util.Map; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReentrantLock;   /**  * @description Thread safe lru cache cache based on LinkedHashMap  * @date 2020/11/2 11:15  */ public class LRUCache<K, V> extends LinkedHashMap<K, V> {     private static final long serialVersionUID = -4407809689385629881L;       private int maxCapacity;       private static final float DEFAULT_LOAD_FACTOR = 0.75f;       private static final int INITIAL_CAPACITY = 16;       private final Lock lock = new ReentrantLock();       public LRUCache(int maxCapacity) {         this(maxCapacity, INITIAL_CAPACITY, DEFAULT_LOAD_FACTOR, true);     }       private LRUCache(int maxCapacity, int initialCapacity, float loadFactor, boolean accessOrder) {         super(initialCapacity, loadFactor, accessOrder);         this.maxCapacity = maxCapacity;     }       @Override     public V get(Object key) {         lock.lock();         try {             return super.get(key);         } finally {             lock.unlock();         }     }       @Override     public V put(K key, V value) {         lock.lock();         try {             return super.put(key, value);         } finally {             lock.unlock();         }     }       @Override     public V remove(Object key) {         lock.lock();         try {             return super.remove(key);         } finally {             lock.unlock();         }     }       @Override     protected boolean removeEldestEntry(Map.Entry<K, V> eldest) {         return size() > maxCapacity;     } }