写一个java缓存池

2018-06-27  本文已影响0人  南京确善能

公司项目个人身份票据验证不唯一,原想用cookie解决,但是移动端没办法存储cookie,然后自己写了一个缓存,不多BB,直接上代码。

/**
 * 
 * @author 黑暗料理界扛把子
 *
 * @Description 缓存实体类  这里自己随意定义成员变量
 */
public class Cache implements Comparable<Cache>{
    
    private String key;//缓存ID
    private String ip;//ip
    private String ticket;//票据
    private long timeOut;//过期时间
    
    public Cache() {
        super();
    }
    
    public String getKey() {
        return key;
    }

    public long getTimeOut() {
        return timeOut;
    }

    public Cache(String key, String ip, String ticket, long timeOut) {
        super();
        this.key = key;
        this.ip = ip;
        this.ticket = ticket;
        this.timeOut = timeOut;
    }

    public String getIp() {
        return ip;
    }

    public void setIp(String ip) {
        this.ip = ip;
    }

    public String getTicket() {
        return ticket;
    }

    public void setTicket(String ticket) {
        this.ticket = ticket;
    }

    public void setKey(String string) {
        key = string;
    }

    public void setTimeOut(long l) {
        timeOut = l;
    }


    @Override
    public int compareTo(Cache o) {
         long r = this.timeOut - o.timeOut;  
         if (r > 0) {  
             return 1;  
         }  
         if (r < 0) {  
             return -1;  
         }  
         return 0;  
    }

}

import java.util.ArrayList;
import java.util.Calendar;
import java.util.Iterator;
import java.util.PriorityQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

import org.apache.log4j.Logger;
/**
 * 
 * @author 黑暗料理界扛把子
 *
 * @Description 缓存实现类
 */
@SuppressWarnings("all")
public class CacheManager {
    
    private static ScheduledExecutorService swapExpiredPool   = new ScheduledThreadPoolExecutor(10);  
    private  ConcurrentHashMap<String, Cache> cacheMap = new ConcurrentHashMap<String, Cache>();
    private  PriorityQueue<Cache> expireQueue = new PriorityQueue<>(1024);  
    private  Lock lock = new ReentrantLock();
    private static final  CacheManager cm=new CacheManager();
    
    Logger logger=Logger.getLogger(CacheManager.class);
   
    private CacheManager() {
        swapExpiredPool.scheduleWithFixedDelay(new TimeOutCacheTask(), 5, 5, TimeUnit.SECONDS); 
    }
    
    public static CacheManager cm() {    
        return cm;
    }
   
    //获取缓存
    public Cache getCache(String key){
        return cacheMap.get(key);
    }
    
    //设置缓存
    public void putCache(String key,Cache cache){
        lock.lock();  
        try {
            if (hasCache(key)) {
                expireQueue.remove(cache);
            }
            expireQueue.add(cache);
            cacheMap.put(key, cache);
        }finally {
             lock.unlock();  
        }
    }
  
    //判断是否存在一个缓存
    private boolean hasCache(String key) {
        return cacheMap.containsKey(key);
    }
  
    //清除所有缓存
    public void clearAll() {
        lock.lock();  
        try {
            cacheMap.clear();
            expireQueue.clear();
        } finally {
            lock.unlock();  
        }
    }
    
    //清除指定的缓存
    public void removeCache(String key) {
        lock.lock();
        try {
            if (hasCache(key)) {
                cacheMap.remove(key);
                expireQueue.remove(getCache(key));
            }
        } finally {
            lock.unlock();  
        }
    }
    
    //获取缓存中的大小
    public int getCacheSize() {
        return cacheMap.size();
    }
    
    //重写载入缓存信息方法
    public void setCache(String key,String ip,String ticket){
        Cache cache = new Cache();
        cache.setKey(key);
        cache.setTimeOut(getTimeInMillis());
        cache.setIp(ip);
        cache.setTicket(ticket);
        putCache(key,cache);
    }
  
    //获取缓存对象中的所有键值名称
    public ArrayList getCaches() {
        ArrayList cacheList = new ArrayList();
        try {
            Iterator i = cacheMap.entrySet().iterator();
            while (i.hasNext()) {
                java.util.Map.Entry entry = (java.util.Map.Entry) i.next();
                cacheList.add((String) entry.getKey());
            }
        } catch (Exception ex) {} finally {
            return cacheList;
        }
    }
    
   //过期时间设置为10天后
    private long getTimeInMillis(){
        Calendar c = Calendar.getInstance();
        c.set(Calendar.DATE,c.get(Calendar.DATE)+10);
        return c.getTimeInMillis();
    }
    
    //删除已经过期的数据 
    private class TimeOutCacheTask implements Runnable {    
        @Override  
        public void run() {  
            long now = System.currentTimeMillis();  
            while (true) {  
                lock.lock();  
                try {  
                    Cache chche = expireQueue.peek();  
                    //没有数据了,或者数据都是没有过期的了  
                    if (chche == null || chche.getTimeOut() > now) {  
                        return;  
                    }  
                    cacheMap.remove(chche.getKey());  
                    expireQueue.poll(); //移除并返回头部元素
                } finally {  
                    lock.unlock();  
                }  
            }  
        }  
    } 
}

采用了单例模式,缓存操作都加了锁,代码通俗易懂,就不多BB了。

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