采用静态Map、ConcurrentHashMap处理缓存

考虑到在使用HashMap在并发时会出现不正确行为，根据网上资料自己编写了采用ConcurrentHashMap来完成静态缓存的处理，目的是为了能够用来处理高并发的线程安全类，如有问题请各位大侠指教：

package com.zengms.cache;import java.util.Map;import java.util.concurrent.ConcurrentHashMap;import org.apache.commons.logging.Log;import org.apache.commons.logging.LogFactory;public class MapCacheManager {private final static Log log = LogFactory.getLog(MapCacheManager.class);private volatile long updateTime = 0L;// 更新缓存时记录的时间private volatile boolean updateFlag = true;// 正在更新时的阀门，为false时表示当前没有更新缓存，为true时表示当前正在更新缓存private volatile static MapCacheManager mapCacheObject;// 缓存实例对象private static Map<String, String> cacheMap = new ConcurrentHashMap<String, String>();// 缓存容器private MapCacheManager() {this.LoadCache();// 加载缓存updateTime = System.currentTimeMillis();// 缓存更新时间}/** * 采用单例模式获取缓存对象实例 *  * @return */public static MapCacheManager getInstance() {if (null == mapCacheObject) {synchronized (MapCacheManager.class) {if (null == mapCacheObject) {mapCacheObject = new MapCacheManager();}}}return mapCacheObject;}/** * 装载缓存 */private void LoadCache() {this.updateFlag = true;// 正在更新/********** 数据处理，将数据放入cacheMap缓存中 **begin ******/cacheMap.put("key1", "value1");cacheMap.put("key2", "value2");cacheMap.put("key3", "value3");cacheMap.put("key4", "value4");cacheMap.put("key5", "value5");/********** 数据处理，将数据放入cacheMap缓存中 ***end *******/this.updateFlag = false;// 更新已完成}/** * 返回缓存对象 *  * @return */public Map<String, String> getMapCache() {long currentTime = System.currentTimeMillis();if (this.updateFlag) {// 前缓存正在更新log.info("cache is Instance .....");return null;}if (this.IsTimeOut(currentTime)) {// 如果当前缓存正在更新或者缓存超出时限，需重新加载synchronized (this) {this.ReLoadCache();this.updateTime = currentTime;}}return this.cacheMap;}private boolean IsTimeOut(long currentTime) {return ((currentTime - this.updateTime) > 1000000);// 超过时限，超时}/** * 获取缓存项大小 * @return */private int getCacheSize() {return cacheMap.size();}/** * 获取更新时间 * @return */private long getUpdateTime() {return this.updateTime;}/** * 获取更新标志 * @return */private boolean getUpdateFlag() {return this.updateFlag;}/** * 重新装载 */private void ReLoadCache() {this.cacheMap.clear();this.LoadCache();}}

测试代码：

package com.zengms.cache;import java.util.Iterator;import java.util.Map;import java.util.Set;import java.util.concurrent.ConcurrentHashMap;public class CacheTest {public static void main(String[] args) {MapCacheManager cache = MapCacheManager.getInstance();Map<String, String> cacheMap = new ConcurrentHashMap<String, String>();cacheMap = cache.getMapCache();Set<String> set = cacheMap.keySet();Iterator<String> it = set.iterator();while(it.hasNext()){String key = it.next();System.out.println(key+"="+cacheMap.get(key));}}}