import java.util.HashMap;import java.util.LinkedHashMap;import java.util.Map;public class LRUCache { private long lookups; private long hits; private long inserts; private long evictions; private Map map; public void init(int initialSize, final int limitSize) { map = new LinkedHashMap(initialSize, 0.75f, true) { protected boolean removeEldestEntry(Map.Entry eldest) { if (size() > limitSize) { evictions++; return true; } return false; } }; } public int size() { synchronized (map) { return map.size(); } } public Object put(Object key, Object value) { synchronized (map) { inserts++; return map.put(key, value); } } public Object get(Object key) { synchronized (map) { Object val = map.get(key); lookups++; if (val != null) { hits++; } return val; } } public void clear() { synchronized (map) { map.clear(); } } private static String calcHitRatio(long lookups, long hits) { if (lookups==0) return "0.00"; if (lookups==hits) return "1.00"; int hundredths = (int)(hits*100/lookups); // rounded down if (hundredths < 10) return "0.0" + hundredths; return "0." + hundredths; } public Map getStatistics(){ Map statMap = new HashMap(); synchronized (map) { statMap.put("lookups", lookups); statMap.put("hits", hits); statMap.put("hitratio", calcHitRatio(lookups,hits)); statMap.put("inserts", inserts); statMap.put("evictions", evictions); statMap.put("size", map.size()); } return statMap; }}
相关参考：http://dennis-zane.iteye.com/blog/128278
