java 手寫 jvm高性能緩存

時間 2019-12-11

標籤 java 手寫 jvm 高性能緩存欄目 Java 简体版

原文原文鏈接

java 手寫 jvm高性能緩存，鍵值對存儲，隊列存儲，存儲超時設置java

緩存接口緩存

package com.ws.commons.cache;

public interface ICache {

    void expire(String key, int timeOutSecond);

    void leftPush(String key, Object value);

    void rightPush(String key, Object value);

    void rightPush(String key, Object value, int timeOutSecond);

    <T> T rightPop(String key);

    <T> T leftPop(String key);

    void put(String key, Object value);

    void put(String key, Object value, int timeOutSecond);

    boolean putIfAbsent(String key, Object value);

    boolean putIfAbsent(String key, Object value, int timeOutSecond);

    <T> T get(String key);

    boolean hasKey(String key);

    void remove(String key);

    <T> T removeAndGet(String key);
}

View Code

實現類jvm

package com.ws.commons.cache;

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentLinkedDeque;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;

import com.ws.commons.tool.ThreadTool;

/**
 * 本地高性能緩存
 * 
 * @author 塵無塵
 *
 */
public class LocalCache implements ICache {

    private static LocalCache staticInstance;

    public static LocalCache instance() {
        if (staticInstance != null) {
            return staticInstance;
        } else {
            synchronized (LocalCache.class) {
                if (staticInstance != null) {
                    return staticInstance;
                }
                staticInstance = new LocalCache();
                return staticInstance;
            }
        }
    }

    private LocalCache() {
    }

    /**
     * 緩存實例
     */
    private static final Map<String, Object> INSTANCE = Collections.synchronizedMap(new LinkedHashMap<>());

    /**
     * 緩存KEY 存儲時間記錄
     */
    private static final Map<String, Long> KEY_TIME_INSTANCE = Collections.synchronizedMap(new LinkedHashMap<>());

    /**
     * 時間格式化對象
     */
    public static final DateTimeFormatter yyyyMMddHHmmss_FMT = DateTimeFormatter.ofPattern("yyyyMMddHHmmss");

    /**
     * 存儲最大數據數量，超出該數據量時，刪除最新存儲的數據
     */
    private static final int MAXCOUNT = 10000;

    /**
     * 清理緩存線程,防止頻繁的緩存清理 建立線程消耗性能
     */
    private static final ExecutorService THREAD_POOL = Executors.newCachedThreadPool();

    /**
     * 清理緩存時線程作的標記
     */
    private static final AtomicInteger TREAM_CACHE_FLAG = new AtomicInteger(0);

    /**
     * 緩存清理 輪詢一圈等待時長
     */
    private static final int TRIM_INTERIM = 2000;

    /**
     * 隊列存儲，在末尾添加元素
     * 
     * @param key
     * @param value
     * @param outSecond 保存時間(秒)，超出時間，被清除
     */
    @SuppressWarnings("unchecked")
    @Override
    public void rightPush(String key, Object value, int outSecond) {
        ConcurrentLinkedDeque<Object> linkList = (ConcurrentLinkedDeque<Object>) INSTANCE.get(key);
        if (linkList == null) {
            linkList = new ConcurrentLinkedDeque<>();
            INSTANCE.put(key, linkList);
        }
        KEY_TIME_INSTANCE.put(key,
                Long.parseLong(LocalDateTime.now().plusSeconds(outSecond).format(yyyyMMddHHmmss_FMT)));
        linkList.offer(value);
        LocalCache.streamInstance();
    }

    /**
     * 隊列存儲，在末尾添加元素
     * 
     * @param key
     * @param value
     */
    @SuppressWarnings("unchecked")
    @Override
    public void rightPush(String key, Object value) {
        ConcurrentLinkedDeque<Object> linkList = (ConcurrentLinkedDeque<Object>) INSTANCE.get(key);
        if (linkList == null) {
            linkList = new ConcurrentLinkedDeque<>();
            INSTANCE.putIfAbsent(key, linkList);
        }
        linkList.offer(value);
        LocalCache.streamInstance();
    }

    /**
     * 隊列存儲，在開頭添加元素
     * 
     * @param key
     * @param value
     */
    @SuppressWarnings("unchecked")
    @Override
    public void leftPush(String key, Object value) {
        ConcurrentLinkedDeque<Object> linkList = (ConcurrentLinkedDeque<Object>) INSTANCE.get(key);
        if (linkList == null) {
            linkList = new ConcurrentLinkedDeque<>();
            INSTANCE.putIfAbsent(key, linkList);
        }
        linkList.offerFirst(value);
        LocalCache.streamInstance();
    }

    /**
     * 刪除隊列的最後一個元素
     * 
     * @param key
     * @return
     */
    @SuppressWarnings("unchecked")
    @Override
    public <T> T rightPop(String key) {
        ConcurrentLinkedDeque<Object> linkList = (ConcurrentLinkedDeque<Object>) INSTANCE.get(key);
        if (linkList == null) {
            return null;
        }
        return (T) linkList.pollLast();
    }

    /**
     * 刪除隊列的第一個元素
     * 
     * @param key
     * @return
     */
    @SuppressWarnings("unchecked")
    @Override
    public <T> T leftPop(String key) {
        ConcurrentLinkedDeque<Object> linkList = (ConcurrentLinkedDeque<Object>) INSTANCE.get(key);
        if (linkList == null) {
            return null;
        }
        return (T) linkList.pollFirst();
    }

    /**
     * 
     * @param key
     * @param value
     */

    @Override
    public void put(String key, Object value) {
        INSTANCE.put(key, value);
        LocalCache.streamInstance();
    }

    /**
     * 
     * @param key
     * @param value
     * @param outSecond 保存時間(秒)，超出時間，被清除
     */
    @Override
    public void put(String key, Object value, int outSecond) {
        INSTANCE.put(key, value);
        KEY_TIME_INSTANCE.put(key,
                Long.parseLong(LocalDateTime.now().plusSeconds(outSecond).format(yyyyMMddHHmmss_FMT)));
        LocalCache.streamInstance();
    }

    /**
     * 
     * @param key
     * @param value
     * @return
     */
    @Override
    public boolean putIfAbsent(String key, Object value) {
        Object result = null;
        result = INSTANCE.putIfAbsent(key, value);
        LocalCache.streamInstance();
        return result == null;
    }

    /**
     * 
     * @param key
     * @param value
     * @param outSecond 保存時間(秒)，超出時間，被清除
     * @return
     */
    @Override
    public boolean putIfAbsent(String key, Object value, int outTimeSecond) {
        Object result = null;
        result = INSTANCE.putIfAbsent(key, value);
        KEY_TIME_INSTANCE.putIfAbsent(key,
                Long.parseLong(LocalDateTime.now().plusSeconds(outTimeSecond).format(yyyyMMddHHmmss_FMT)));
        LocalCache.streamInstance();
        return result == null;
    }

    /**
     * 獲取緩存
     * 
     * @param key
     * @return
     */
    @SuppressWarnings("unchecked")
    @Override
    public <T> T get(String key) {
        T value = (T) INSTANCE.get(key);
        if (value == null) {
            return null;
        }
        if (LocalCache.isTimeOut(key)) {
            INSTANCE.remove(key);
            KEY_TIME_INSTANCE.remove(key);
            return null;
        } else {
            return value;
        }
    }

    @Override
    public void expire(String key, int timeOutSecond) {
        KEY_TIME_INSTANCE.put(key,
                Long.parseLong(LocalDateTime.now().plusSeconds(timeOutSecond).format(yyyyMMddHHmmss_FMT)));
    }

    /**
     * 是否含有
     * 
     * @param key
     * @return
     */
    @Override
    public boolean hasKey(String key) {
        return INSTANCE.containsKey(key);
    }

    /**
     * 刪除
     * 
     * @param id
     * @return
     */
    @Override
    public void remove(String key) {
        INSTANCE.remove(key);
    }

    /**
     * 刪除並返回
     * 
     * @param id
     * @return
     */
    @SuppressWarnings("unchecked")
    @Override
    public <T> T removeAndGet(String key) {
        return (T) INSTANCE.remove(key);
    }

    /**
     * 整理緩存：<br>
     * 整理的緩存的線程只能一個，節約資源開銷<br>
     * TRIM_INTERIM<br>
     */
    private static void streamInstance() {

        if (TREAM_CACHE_FLAG.incrementAndGet() > 1) {
            return;
        }
        THREAD_POOL.execute(() -> {
            long now = Long.parseLong(LocalDateTime.now().format(yyyyMMddHHmmss_FMT));
            do {
                /*
                 * 一、超時緩存清除
                 */
                Iterator<Entry<String, Object>> instanceIt = INSTANCE.entrySet().iterator();
                while (instanceIt.hasNext()) {
                    String key = instanceIt.next().getKey();
                    if (LocalCache.isTimeOut(key, now)) {
                        instanceIt.remove();
                        KEY_TIME_INSTANCE.remove(key);
                    }
                }

                /*
                 * 二、 超容量,從首位開始清除
                 */
                if (INSTANCE.size() > MAXCOUNT) {
                    List<String> tempList = new ArrayList<>();
                    for (Entry<String, Object> en : INSTANCE.entrySet()) {
                        tempList.add(en.getKey());
                        if (INSTANCE.size() - tempList.size() <= MAXCOUNT) {
                            tempList.forEach(e -> {
                                INSTANCE.remove(e);
                                KEY_TIME_INSTANCE.remove(e);
                            });
                            break;
                        }
                    }
                }

                ThreadTool.sleep(TRIM_INTERIM);
                now = Long.valueOf(LocalDateTime.now().format(yyyyMMddHHmmss_FMT));
            } while (!INSTANCE.isEmpty());
            TREAM_CACHE_FLAG.set(0);
        });
    }

    /**
     * 判斷key對比當前時間是否超時
     * 
     * @param key
     * @return
     */
    private static boolean isTimeOut(String key) {
        long now = Long.parseLong(LocalDateTime.now().format(yyyyMMddHHmmss_FMT));
        return LocalCache.isTimeOut(key, now);
    }

    /**
     * 
     * 判斷key對比now是否超時
     * 
     * @param key
     * @param now
     * @return
     */
    private static boolean isTimeOut(String key, long now) {
        Long saveTime = KEY_TIME_INSTANCE.get(key);
        return saveTime == null || saveTime < now;
    }
}