import java.util.LinkedHashMap;import java.util.concurrent.locks.Lock;import java.util.concurrent.locks.ReentrantLock;public class LRUCache
    
      extends LinkedHashMap
     
       {	private static final long serialVersionUID = -656812640814484468L;	/** 默认最大容量 */	private static final int DEFAULT_MAX_CAPACITY = 300;	private static final int INITIALCAPACITY = 16;	/** 负载因子 */	private static final float DEFAULT_LOAD_FACTOR = 0.75f;	private final Lock lock = new ReentrantLock();	private volatile int maxCapacity;	/**	 * 
      
	 * ------------------------------
      
	 */	public LRUCache() {		this(DEFAULT_MAX_CAPACITY);	}	public LRUCache(int maxCapacity) {		super(INITIALCAPACITY, DEFAULT_LOAD_FACTOR, Boolean.TRUE);		this.maxCapacity = maxCapacity;	}	@Override	protected boolean removeEldestEntry(java.util.Map.Entry
      
        eldest) {		return size() > maxCapacity;	}	@Override	public V get(Object key) {		try {			lock.lock();			return super.get(key);		} finally {			lock.unlock();		}	}	public V put(K key, V value) {		try {			lock.lock();			return super.put(key, value);		} finally {			lock.unlock();		}	}	@Override	public V remove(Object key) {		try {			lock.lock();			return super.remove(key);		} finally {			lock.unlock();		}	}	@Override	public boolean containsKey(Object key) {		try {			lock.lock();			return super.containsKey(key);		} finally {			lock.unlock();		}	}	@Override	public void clear() {		try {			lock.lock();			super.clear();		} finally {			lock.unlock();		}	}	@Override	public int size() {		try {			lock.lock();			return super.size();		} finally {			lock.unlock();		}	}	/**	 * 获得maxCapacity	 * @return the maxCapacity	 */	public int getMaxCapacity() {		return maxCapacity;	}	/**	 * 设置maxCapacity	 * @param maxCapacity the maxCapacity to set	 */	public void setMaxCapacity(int maxCapacity) {		this.maxCapacity = maxCapacity;	}}
      
     
    

public class Main {		public static void main(String[] args) {		LRUCache
    
      lruCache = new LRUCache
     
      (2);		lruCache.put("1", "1");		lruCache.put("2", "2");		System.out.println(lruCache);		lruCache.put("3", "3");		System.out.println(lruCache);	}}
     
    

{1=1, 2=2}

{2=2, 3=3}