可以实现不等待,线程自动更新缓存
java动态缓存jar包请下载。
源代码:
CacheData.java 存放缓存数据的Bean
CacheOperation.java 缓存处理类
package com.cari.web.cache;
import java.lang.reflect.Method; import java.util.ArrayList; import java.util.Arrays; import java.util.Hashtable;
import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory;
/** *//** * @author zsy */ public class CacheOperation ...{ private static final Log log = LogFactory.getLog(CacheOperation.class); private static CacheOperation singleton = null; private Hashtable cacheMap;//存放缓存数据 private ArrayList threadKeys;//处于线程更新中的key值列表 public static CacheOperation getInstance() ...{ if (singleton == null) ...{ singleton = new CacheOperation(); } return singleton; } private CacheOperation() ...{ cacheMap = new Hashtable(); threadKeys = new ArrayList(); } /** *//** * 添加数据缓存 * 与方法getCacheData(String key, long intervalTime, int maxVisitCount)配合使用 * @param key * @param data */ public void addCacheData(String key, Object data) ...{ addCacheData(key, data, true); } private void addCacheData(String key, Object data, boolean check) ...{ if (Runtime.getRuntime().freeMemory() < 5L*1024L*1024L) ...{//虚拟机内存小于10兆,则清除缓存 log.warn("WEB缓存:内存不足,开始清空缓存!"); removeAllCacheData(); return; } else if(check && cacheMap.containsKey(key)) ...{ log.warn("WEB缓存:key值= " + key + " 在缓存中重复, 本次不缓存!"); return; } cacheMap.put(key, new CacheData(data)); } /** *//** * 取得缓存中的数据 * 与方法addCacheData(String key, Object data)配合使用 * @param key * @param intervalTime 缓存的时间周期,小于等于0时不限制 * @param maxVisitCount 访问累积次数,小于等于0时不限制 * @return */ public Object getCacheData(String key, long intervalTime, int maxVisitCount) ...{ CacheData cacheData = (CacheData)cacheMap.get(key); if (cacheData == null) ...{ return null; } if (intervalTime > 0 && (System.currentTimeMillis() - cacheData.getTime()) > intervalTime) ...{ removeCacheData(key); return null; } if (maxVisitCount > 0 && (maxVisitCount - cacheData.getCount()) <= 0) ...{ removeCacheData(key); return null; } else ...{ cacheData.addCount(); } return cacheData.getData(); } /** *//** * 当缓存中数据失效时,用不给定的方法线程更新数据 * @param o 取得数据的对像(该方法是静态方法是不用实例,则传Class实列) * @param methodName 该对像中的方法 * @param parameters 该方法的参数列表(参数列表中对像都要实现toString方法,若列表中某一参数为空则传它所属类的Class) * @param intervalTime 缓存的时间周期,小于等于0时不限制 * @param maxVisitCount 访问累积次数,小于等于0时不限制 * @return */ public Object getCacheData(Object o, String methodName,Object[] parameters, long intervalTime, int maxVisitCount) ...{ Class oc = o instanceof Class ? (Class)o : o.getClass(); StringBuffer key = new StringBuffer(oc.getName());//生成缓存key值 key.append("-").append(methodName); if (parameters != null) ...{ for (int i = 0; i < parameters.length; i++) ...{ if (parameters[i] instanceof Object[]) ...{ key.append("-").append(Arrays.toString((Object[])parameters[i])); } else ...{ key.append("-").append(parameters[i]); } } } CacheData cacheData = (CacheData)cacheMap.get(key.toString()); if (cacheData == null) ...{//等待加载并返回 Object returnValue = invoke(o, methodName, parameters, key.toString()); return returnValue instanceof Class ? null : returnValue; } if (intervalTime > 0 && (System.currentTimeMillis() - cacheData.getTime()) > intervalTime) ...{ daemonInvoke(o, methodName, parameters, key.toString());//缓存时间超时,启动线程更新数据 } else if (maxVisitCount > 0 && (maxVisitCount - cacheData.getCount()) <= 0) ...{//访问次数超出,启动线程更新数据 daemonInvoke(o, methodName, parameters, key.toString()); } else ...{ cacheData.addCount(); } return cacheData.getData(); } /** *//** * 递归调用给定方法更新缓存中数据据 * @param o * @param methodName * @param parameters * @param key * @return 若反射调用方法返回值为空则返回该值的类型 */ private Object invoke(Object o, String methodName,Object[] parameters, String key) ...{ Object returnValue = null; try ...{ Class[] pcs = null; if (parameters != null) ...{ pcs = new Class[parameters.length]; for (int i = 0; i < parameters.length; i++) ...{ if (parameters[i] instanceof MethodInfo) ...{//参数类型是MethodInfo则调用该方法的返回值做这参数 MethodInfo pmi = (MethodInfo)parameters[i]; Object pre = invoke(pmi.getO(), pmi.getMethodName(), pmi.getParameters(), null); parameters[i] = pre; } if (parameters[i] instanceof Class) ...{ pcs[i] = (Class)parameters[i]; parameters[i] = null; } else ...{ pcs[i] = parameters[i].getClass(); } } } Class oc = o instanceof Class ? (Class)o : o.getClass(); // Method m = oc.getDeclaredMethod(methodName, pcs); Method m = matchMethod(oc, methodName, pcs); returnValue = m.invoke(o, parameters); if (key != null && returnValue != null) ...{ addCacheData(key, returnValue, false); } if (returnValue == null) ...{ returnValue = m.getReturnType(); } } catch(Exception e) ...{ log.error("调用方法失败,methodName=" + methodName); if (key != null) ...{ removeCacheData(key); log.error("更新缓存失败,缓存key=" + key); } e.printStackTrace(); } return returnValue; } /** *//** * 找不到完全匹配的方法时,对参数进行向父类匹配 * 因为方法aa(java.util.List) 与 aa(java.util.ArrayList)不能自动匹配到 * * @param oc * @param methodName * @param pcs * @return * @throws NoSuchMethodException * @throws NoSuchMethodException */ private Method matchMethod(Class oc, String methodName, Class[] pcs ) throws NoSuchMethodException, SecurityException ...{ try ...{ Method method = oc.getDeclaredMethod(methodName, pcs);
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