ConcurrentMap实现本地缓存，LocalCacheUtil.工具类

最新推荐文章于 2025-03-07 14:28:27 发布

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#java #缓存 #mysql #redis #数据库

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本文介绍了一个利用Java中ConcurrentMap实现的本地缓存工具类LocalCacheUtil，该工具类能够有效地管理本地缓存数据，并提供了一种简单的方法来设置、获取和删除缓存项。此外，还提供了一个具体的使用示例，展示了如何将数据库连接存储到本地缓存中。

ConcurrentMap实现本地缓存，LocalCacheUtil.工具类,可直接使用！

LocalCacheUtil.java

package org.jeecg.bigdata.common.dataSource.utils;

import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 * local cache tool
 *
 * @author xuxueli 2018-01-22 21:37:34
 */
public class LocalCacheUtil {
    private static ConcurrentMap<String, LocalCacheData> cacheRepository = new ConcurrentHashMap<String, LocalCacheData>();   // 类型建议用抽象父类，兼容性更好；
    private static class LocalCacheData{
        private String key;
        private Object val;
        private long timeoutTime;
        public LocalCacheData() {
        }
        public LocalCacheData(String key, Object val, long timeoutTime) {
            this.key = key;
            this.val = val;
            this.timeoutTime = timeoutTime;
        }
        public String getKey() {
            return key;
        }
        public void setKey(String key) {
            this.key = key;
        }
        public Object getVal() {
            return val;
        }
        public void setVal(Object val) {
            this.val = val;
        }
        public long getTimeoutTime() {
            return timeoutTime;
        }
        public void setTimeoutTime(long timeoutTime) {
            this.timeoutTime = timeoutTime;
        }
    }


    /**
     * set cache
     *
     * @param key
     * @param val
     * @param cacheTime
     * @return
     */
    public static boolean set(String key, Object val, long cacheTime){
        // clean timeout cache, before set new cache (avoid cache too much)
        cleanTimeoutCache();
        // set new cache
        if (key==null || key.trim().length()==0) {
            return false;
        }
        if (val == null) {
            remove(key);
        }
        if (cacheTime <= 0) {
            remove(key);
        }
        long timeoutTime = System.currentTimeMillis() + cacheTime;
        LocalCacheData localCacheData = new LocalCacheData(key, val, timeoutTime);
        cacheRepository.put(localCacheData.getKey(), localCacheData);
        return true;
    }

    /**
     * remove cache
     *
     * @param key
     * @return
     */
    public static boolean remove(String key){
        if (key==null || key.trim().length()==0) {
            return false;
        }
        cacheRepository.remove(key);
        return true;
    }

    /**
     * get cache
     *
     * @param key
     * @return
     */
    public static Object get(String key){
        if (key==null || key.trim().length()==0) {
            return null;
        }
        LocalCacheData localCacheData = cacheRepository.get(key);
        if (localCacheData!=null && System.currentTimeMillis()<localCacheData.getTimeoutTime()) {
            return localCacheData.getVal();
        } else {
            remove(key);
            return null;
        }
    }

    /**
     * clean timeout cache
     *
     * @return
     */
    public static boolean cleanTimeoutCache(){
        if (!cacheRepository.keySet().isEmpty()) {
            for (String key: cacheRepository.keySet()) {
                LocalCacheData localCacheData = cacheRepository.get(key);
                if (localCacheData!=null && System.currentTimeMillis()>=localCacheData.getTimeoutTime()) {
                    cacheRepository.remove(key);
                }
            }
        }
        return true;
    }
}

测试使用：将数据库链接存到本地缓存（部分代码）

 if (null==LocalCacheUtil.get(jobDatasource.getName())) {
            getDataSource(jobDatasource);
        } else {
            this.connection = (Connection) LocalCacheUtil.get(jobDatasource.getName());
            if (!this.connection.isValid(500)) {
                LocalCacheUtil.remove(jobDatasource.getName());
                getDataSource(jobDatasource);
            }
        }
  LocalCacheUtil.set(jobDatasource.getName(), this.connection, 4 * 60 * 60 * 1000);