java 使用靜態hashmap實現簡單緩衝

標籤：java   info   private   long   lld   obj   expired   使用   布爾   

因項目需要的資料查詢較多，數量大，所以要用到緩衝，在未引用redis的情況下，僅僅只做一個速度的提升

1、Cache類

public class Cache<E> {
    private String key;//緩衝ID，根據iD往hashmap存放值
    private E value;//快取資料 ，需要緩衝的對象實體
    private long timeOut;//更新時間
    private boolean expired; //是否到期
    public Cache() {
        super();
    }

    public Cache(String key, E value, long timeOut, boolean expired) {
        this.key = key;
        this.value = value;
        this.timeOut = timeOut+System.currentTimeMillis();
        this.expired = expired;
    }

    public String getKey() {
        return key;
    }

    public long getTimeOut() {
        return timeOut;
    }

    public E getValue() {
        return value;
    }

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

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

    public void setValue(E object) {
        value = object;
    }

    public boolean isExpired() {
        return expired;
    }

    public void setExpired(boolean b) {
        expired = b;
    }
}

2、CacheManager類

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;

/**
 * Created by admin on 2018/1/2.
 */
public class CacheManager {
    private static HashMap cacheMap = new HashMap();

    //單一實例構造方法
    private CacheManager() {
        super();
    }
    //擷取布爾值的緩衝
    public static boolean getSimpleFlag(String key){
        try{
            return (Boolean) cacheMap.get(key);
        }catch(NullPointerException e){
            return false;
        }
    }
    public static long getServerStartdt(String key){
        try {
            return (Long)cacheMap.get(key);
        } catch (Exception ex) {
            return 0;
        }
    }
    //設定布爾值的緩衝
    public synchronized static boolean setSimpleFlag(String key,boolean flag){
        if (flag && getSimpleFlag(key)) {//假如為真不允許被覆蓋
            return false;
        }else{
            cacheMap.put(key, flag);
            return true;
        }
    }
    public synchronized static boolean setSimpleFlag(String key,long serverbegrundt){
        if (cacheMap.get(key) == null) {
            cacheMap.put(key,serverbegrundt);
            return true;
        }else{
            return false;
        }
    }

    //得到緩衝。同步靜態方法
    private synchronized static Cache getCache(String key) {
        return (Cache) cacheMap.get(key);
    }

    //判斷是否存在一個緩衝
    private synchronized static boolean hasCache(String key) {
        return cacheMap.containsKey(key);
    }

    //清除所有緩衝
    public synchronized static void clearAll() {
        cacheMap.clear();
    }

    //清除某一類特定緩衝,通過遍曆HASHMAP下的所有對象，來判斷它的KEY與傳入的TYPE是否匹配
    public synchronized static void clearAll(String type) {
        Iterator i = cacheMap.entrySet().iterator();
        String key;
        ArrayList<String> arr = new ArrayList();
        try {
            while (i.hasNext()) {
                java.util.Map.Entry entry = (java.util.Map.Entry) i.next();
                key = (String) entry.getKey();
                if (key.startsWith(type)) { //如果匹配則刪除掉
                    arr.add(key);
                }
            }
            for (int k = 0; k < arr.size(); k++) {
                clearOnly(arr.get(k));
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }

    //清除指定的緩衝
    public synchronized static void clearOnly(String key) {
        cacheMap.remove(key);
    }

    //載入緩衝
    public synchronized static void putCache(String key, Cache obj) {
        cacheMap.put(key, obj);
    }

    //擷取緩衝資訊
    public static Cache getCacheInfo(String key) {

        if (hasCache(key)) {
            Cache cache = getCache(key);
            if (cacheExpired(cache)) { //調用判斷是否終止方法
                cache.setExpired(true);
                cacheMap.remove(key);
                return null;
            }
            return cache;
        }else{
            return null;
        }

    }

    //載入緩衝資訊
    public static void putCacheInfo(String key, Cache obj, long dt,boolean expired) {
        Cache cache = new Cache();
        cache.setKey(key);
        cache.setTimeOut(dt + System.currentTimeMillis()); //設定多久後更新緩衝
        cache.setValue(obj);
        cache.setExpired(expired); //緩衝預設載入時，終止狀態為FALSE
        cacheMap.put(key, cache);
    }
    //重寫載入緩衝資訊方法
    public static void putCacheInfo(String key,Cache obj,long dt){
        Cache cache = new Cache();
        cache.setKey(key);
        cache.setTimeOut(dt+System.currentTimeMillis());
        cache.setValue(obj);
        cache.setExpired(false);
        cacheMap.put(key,cache);
    }

    //判斷緩衝是否終止
    public static boolean cacheExpired(Cache cache) {
        if (null == cache) { //傳入的緩衝不存在
            return false;
        }
        long nowDt = System.currentTimeMillis(); //系統當前的毫秒數
        long cacheDt = cache.getTimeOut(); //緩衝內的到期毫秒數
        if (cacheDt <= 0||cacheDt>nowDt) { //到期時間小於等於零時,或者到期時間大於目前時間時，則為FALSE
            return false;
        } else { //大於到期時間 即到期
            return true;
        }
    }

    //擷取緩衝中的大小
    public static int getCacheSize() {
        return cacheMap.size();
    }

    //擷取指定的類型的大小
    public static int getCacheSize(String type) {
        int k = 0;
        Iterator i = cacheMap.entrySet().iterator();
        String key;
        try {
            while (i.hasNext()) {
                java.util.Map.Entry entry = (java.util.Map.Entry) i.next();
                key = (String) entry.getKey();
                if (key.indexOf(type) != -1) { //如果匹配則刪除掉
                    k++;
                }
            }
        } catch (Exception ex) {
            ex.printStackTrace();
        }

        return k;
    }

    //擷取緩衝對象中的所有索引值名稱
    public static ArrayList getCacheAllkey() {
        ArrayList a = new ArrayList();
        try {
            Iterator i = cacheMap.entrySet().iterator();
            while (i.hasNext()) {
                java.util.Map.Entry entry = (java.util.Map.Entry) i.next();
                a.add((String) entry.getKey());
            }
        } catch (Exception ex) {} finally {
            return a;
        }
    }

    //擷取緩衝對象中指定類型 的索引值名稱
    public static ArrayList getCacheListkey(String type) {
        ArrayList a = new ArrayList();
        String key;
        try {
            Iterator i = cacheMap.entrySet().iterator();
            while (i.hasNext()) {
                java.util.Map.Entry entry = (java.util.Map.Entry) i.next();
                key = (String) entry.getKey();
                if (key.indexOf(type) != -1) {
                    a.add(key);
                }
            }
        } catch (Exception ex) {} finally {
            return a;
        }
    }
}

 

3、調用

    @Override
    public DcJqrfbView getMap(String qlinkId, String country, String online, String devtype, String devtype1, String beautify,String adminQLinkId) throws Exception {
        DcJqrfbView viewRespons=new DcJqrfbView();
        String cache_key=new StringBuilder().append(qlinkId).append(country).append(online).append(devtype).append(devtype1).append(beautify).append(adminQLinkId).toString();
        Cache<DcJqrfbView> c = CacheManager.getCacheInfo(cache_key);
        if(c!=null&&!c.isExpired()){
            return  c.getValue();
        }else{
            c  = new Cache(cache_key,viewRespons,10*60*1000,false);
        }
        int positionFialdNum=0;
        int noActivityNum=0;
        List<DcJqrfb> allData=new ArrayList<DcJqrfb>();
        List<DcJqrfb> data=new ArrayList<DcJqrfb>();
        DcWebResponse<List<DcJqrfb>> response=new DcWebResponse<List<DcJqrfb>>();
        Map<String,DcJqrfb> map=new HashMap<String,DcJqrfb>();
        response.setSuccess(true);
    
        response.setData(data);
        viewRespons.setResponse(response);
        viewRespons.setPositionFialdNum(positionFialdNum);
        viewRespons.setNoActivityNum(noActivityNum);
        CacheManager.putCache(cache_key,c);
        return viewRespons;
    }

java 使用靜態hashmap實現簡單緩衝