用LinkedHashMap实现LRU缓存

package com.chan;
import java.util.LinkedHashMap;
import java.util.Map;

public class LRUcache {
    static class LRUCache<K,V> extends LinkedHashMap<K,V>{
        private  static final int MAX_ENTRIES = 3;


        protected  boolean removeEldestEntry(Map.Entry eldest){
                return size()>MAX_ENTRIES;
        }

        LRUCache(){
            super(MAX_ENTRIES,0.75f,true);
        }
    }


    public static void main(String[] args){
        LRUCache<Integer,String> cache= new LRUCache<>();
        cache.put(1, "a");
        cache.put(2, "b");
        cache.put(3, "c");
        cache.get(1);
        cache.put(4, "d");
        System.out.println(cache.keySet());
    }
}

输出结果

[3, 1, 4]