java多线程使用LRU算法实现cache

java多线程使用LRU算法实现cache,第1张

package com.zq.utils;

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import java.util.*;
import java.util.concurrent.ConcurrentHashMap;

@Component
public class FileCacheUtils {

    @Data
    @AllArgsConstructor
    @NoArgsConstructor
    private static class Value{
        private Map<String,Object> data=new HashMap<>();
        private Date expireTime;
    }
    @NoArgsConstructor
    @AllArgsConstructor
    @Data
    private static class Node{
        private String key;
        private Date expireTime;
    }
    // key:uuid
    // value:locationAddress
    private static final Logger logger= LoggerFactory.getLogger(FileCacheUtils.class);
    private static final Map<String,Value> MAP =new ConcurrentHashMap<>();
    private static final PriorityQueue<Node> QUEUE=new PriorityQueue<>(new Comparator<Node>() {
        @Override
        public int compare(Node o1, Node o2) {
            return o1.expireTime.compareTo(o2.expireTime);
        }
    });
    private static final long EXPIRE_TIME=2*60*60*1000;
    private static final int MAXSIZE=1000000;
    public static Map<String, Object> get(String uuid){
        if (uuid==null)
            return null;
        Value value = MAP.get(uuid);
        if(value!=null){
            value.setExpireTime(new Date(System.currentTimeMillis()+EXPIRE_TIME));
            return value.getData();
        }
        return null;
    }
    public static void put(String uuid,Map<String,Object> data){
        Date expireTime=new Date(System.currentTimeMillis()+EXPIRE_TIME);
        MAP.put(uuid,new Value(data,expireTime));
        QUEUE.add(new Node(uuid,expireTime));
        logger.info("添加完成,MAP.size="+MAP.size());
        cleanSizeExceedData();
    }
    public static void cleanExpireData(){
        Node node=QUEUE.peek();
        Date expireTime=new Date(System.currentTimeMillis()-EXPIRE_TIME);
        while(node!=null&&node.expireTime.compareTo(expireTime)<0){
            MAP.remove(node.getKey());
            QUEUE.poll();
            node= QUEUE.peek();
        }
        logger.info("过期清理完成,MAP.size="+MAP.size());
    }
    public static void cleanSizeExceedData(){
        if(MAP.size()<=MAXSIZE)
            return;
        while(MAP.size()>MAXSIZE){
            Node node=QUEUE.poll();
            MAP.remove(node.getKey());
        }
        logger.info("超限请理完成,MAP.size="+MAP.size());
    }
    //设置定时器,20分组调用一次clean()
    @Scheduled(fixedDelay = 20*60*1000)
    public void process(){
        logger.info("定时器调用,MAP.size="+MAP.size());
        cleanSizeExceedData();
        cleanExpireData();
    }
}

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原文地址: http://outofmemory.cn/langs/759223.html

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