JAVAWEB缓存技术.doc

可以实现不等待，线程自动更新缓存。CacheData.java 存放缓存数据的Bean01.packagecom.cari.web.cache;02./*03.* author zsy04.*05.*/06.publicclassCacheData 07.privateObject data;08.privatelongtime;09.privateintcount;10.11.publicCacheData() 5.publicCacheData(Object data,longtime,intcount) 16.this.data = data;17.this.time = time;18.this.count = count;19.20.21.publicCacheData(Object data) 22.this.data = data;23.this.time = System.currentTimeMillis();24.this.count =1;25.26.27.publicvoidaddCount() 28.count+;29.30.31.publicintgetCount() 32.returncount;33.34.publicvoidsetCount(intcount) 35.this.count = count;36.37.publicObject getData() 38.returndata;39.40.publicvoidsetData(Object data) 41.this.data = data;42.43.publiclonggetTime() 44.returntime;45.46.publicvoidsetTime(longtime) 47.this.time = time;48.49.CacheOperation.java 缓存处理类001.packagecom.cari.web.cache;002.importjava.lang.reflect.Method;003.importjava.util.ArrayList;004.importjava.util.Arrays;005.importjava.util.Hashtable;006.mons.logging.Log;007.mons.logging.LogFactory;008./*009.* author zsy010.*/011.publicclassCacheOperation 012.privatestaticfinalLog log = LogFactory.getLog(CacheOperation.class);013.privatestaticCacheOperation singleton =null;014.015.privateHashtable cacheMap;/存放缓存数据016.017.privateArrayList threadKeys;/处于线程更新中的key值列表018.019.publicstaticCacheOperation getInstance() 020.if(singleton =null) 021.singleton =newCacheOperation();022.023.returnsingleton;024.025.026.privateCacheOperation() 027.cacheMap =newHashtable();028.threadKeys =newArrayList();029.030.031./*032.* 添加数据缓存033.* 与方法getCacheData(String key, long intervalTime, int maxVisitCount)配合使用034.* param key035.* param data036.*/037.publicvoidaddCacheData(String key, Object data) 038.addCacheData(key, data,true);039.040.041.privatevoidaddCacheData(String key, Object data,booleancheck) 042.if(Runtime.getRuntime().freeMemory() 0& (System.currentTimeMillis() - cacheData.getTime() intervalTime) 067.removeCacheData(key);068.returnnull;069.070.if(maxVisitCount 0& (maxVisitCount - cacheData.getCount() =0) 071.removeCacheData(key);072.returnnull;073.else074.cacheData.addCount();075.076.returncacheData.getData();077.078.079./*080.* 当缓存中数据失效时，用不给定的方法线程更新数据081.* 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)082.* param methodName 该对像中的方法083.* 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)084.* param intervalTime 缓存的时间周期，小于等于0时不限制085.* param maxVisitCount 访问累积次数，小于等于0时不限制086.* return087.*/088.publicObject getCacheData(Object o, String methodName,Object parameters,089.longintervalTime,intmaxVisitCount) 090.Class oc = oinstanceofClass ? (Class)o : o.getClass();091.StringBuffer key =newStringBuffer(oc.getName();/生成缓存key值092.key.append(-).append(methodName);093.if(parameters !=null) 094.for(inti =0; i 0& (System.currentTimeMillis() - cacheData.getTime() intervalTime) 109.daemonInvoke(o, methodName, parameters, key.toString();/缓存时间超时,启动线程更新数据110.elseif(maxVisitCount 0& (maxVisitCount - cacheData.getCount() =0) /访问次数超出,启动线程更新数据111.daemonInvoke(o, methodName, parameters, key.toString();112.else113.cacheData.addCount();114.115.returncacheData.getData();116.117.118./*119.* 递归调用给定方法更新缓存中数据据120.* param o121.* param methodName122.* param parameters123.* param key124.* return 若反射调用方法返回值为空则返回该值的类型125.*/126.privateObject invoke(Object o, String methodName,Object parameters, String key) 127.Object returnValue =null;128.try129.Class pcs =null;130.if(parameters !=null) 131.pcs =newClassparameters.length;132.for(inti =0; i parameters.length; i+) 133.if(parametersiinstanceofMethodInfo) /参数类型是MethodInfo则调用该方法的返回值做这参数134.MethodInfo pmi = (MethodInfo)parametersi;135.Object pre = invoke(pmi.getO(), pmi.getMethodName(), pmi.getParameters(),null);136.parametersi = pre;137.138.if(parametersiinstanceofClass) 139.pcsi = (Class)parametersi;140.parametersi =null;141.else142.pcsi = parametersi.getClass();46.Class oc = oinstanceofClass ? (Class)o : o.getClass();147./ Method m = oc.getDeclaredMethod(methodName, pcs);148.Method m = matchMethod(oc, methodName, pcs);149.returnValue = m.invoke(o, parameters);150.if(key !=null& returnValue !=null) 151.addCacheData(key, returnValue,false);152.153.if(returnValue =null) 154.returnValue = m.getReturnType();155.156.catch(Exception e) 157.log.error(调用方法失败,methodName=+ methodName);158.if(key !=null) 159.removeCacheData(key);160.log.error(更新缓存失败，缓存key=+ key);161.162.e.printStackTrace();163.164.returnreturnValue;165.166.167./*168.* 找不到完全匹配的方法时,对参数进行向父类匹配169.* 因为方法aa(java.util.List) 与 aa(java.util.ArrayList)不能自动匹配到170.*171.* param oc172.* param methodName173.* param pcs174.* return175.* throws NoSuchMethodException176.* throws NoSuchMethodException177.*/178.privateMethod matchMethod(Class oc, String methodName, Class pcs179.)throwsNoSuchMethodException, SecurityException 180.try181.Method method = oc.getDeclaredMethod(methodName, pcs);182.returnmethod;183.catch(NoSuchMethodException e) 184.Method ms = oc.getDeclaredMethods();185.aa:for(inti =0; i ms.length; i+) 186.if(msi.getName().equals(methodName) 187.Class pts = msi.getParameterTypes();188.if(pts.length = pcs.length) 189.for(intj =0; j pts.length; j+) 190.if(!ptsj.isAssignableFrom(pcsj) 191.breakaa;192.193.194.returnmsi;98.thrownewNoSuchMethodException();02./*203.* 新启线程后台调用给定方法更新缓存中数据据204.* param o205.* param methodName206.* param parameters207.* param key208.*/209.privatevoiddaemonInvoke(Object o, String methodName,Object parameters, String key) 210.if(!threadKeys.contains(key) 211.InvokeThread t =newInvokeThread(o, methodName, parameters, key);212.t.start();16./*217.* 些类存放方法的主调对像,名称及参数数组218.* author zsy219.*220.*/221.publicclassMethodInfo 222.privateObject o;223.privateString methodName;224.privateObject parameters;225.publicMethodInfo(Object o, String methodName,Object parameters) 226.this.o = o;227.this.methodName = methodName;228.this.parameters = parameters;229.230.publicString getMethodName() 231.returnmethodName;232.233.publicvoidsetMethodName(String methodName) 234.this.methodName = methodName;235.236.publicObject getO() 237.returno;238.239.publicvoidsetO(Object o) 240.this.o = o;241.242.publicObject getParameters() 243.returnparameters;244.245.publicvoidsetParameters(Object parameters) 246.this.parameters = parameters;247.248.249.publicString toString() 250.StringBuffer str =newStringBuffer(methodName);251.if(parameters !=null) 252.str.append();253.for(inti =0; i parameters.length; i+) 254.if(parametersiinstanceofObject) 255.str.append(Arrays.toString(Object)parametersi).append(,);256.else257.str.append(parametersi).append(,);258.259.260.str.append();261.262.returnstr.toString();263.264.265.266./*267.* 线程调用方法268.* author zsy269.*270.*/271.privateclassInvokeThreadextendsThread 272.privateObject o;273.privateString methodName;274.privateObject parameters;275.privateString key;276.publicInvokeThread(Object o, String methodName,Object parameters, String key) 277.this.o = o;278.this.methodName = methodName;279.this.parameters = parameters;280.this.key = key;281.282.283.publicvoidrun() 284.threadKeys.add(key);285.invoke(o, methodName, parameters, key);286.threadKeys.remove(key);287.288.289.290./*291.* 移除缓存中的数据292.* param key293.*/294.publicvoidremoveCacheData(String key) 295.cacheMap.remove(key);296.297.298./*299.* 移除所有缓存中的数据300.*301.*/302.publicvoidremoveAllCacheData() 303.cacheMap.clear();304.305.306.publicString toString() 307.StringBuffer sb =newStringBuffer(* );308.sb.append(正在更新的缓存数据： );309.for(inti =0; i threadKeys.size(); i+) 310.sb.append(threadKeys.get(i).append( );311.312.sb.append(当前缓存大小：).append(cacheMap.size().append( );313.sb.append(*);314.returnsb.toString();315.316.用法：例1：代码片段如下：public class Test String rulStr=.;String encoding=.;public void getData() DataCreator c = new DataCreator(); String result = c.initUrlData(urlStr,encoding); System.out.println(result);每次执行上面代码时都要通过调用 initUrlData方法取得数据，假设此方法很耗资源而耗时间，但对数据时实性要求不高，就是可以用以下方式进行缓存处理，保证很快地取得数据，并根据设置的参数自动更新缓存中数据注意：initUrlData方法参数值一样时才属于同一个缓存，否则会生成一个新的缓存，也就是说从缓存中取数据与initUrlData方法参数值有关.public void getData() DataCreator data = new DataCreator(); CacheOperation co = CacheOperation.getInstance(); String str = (String)co.getCacheData(data, initUrlData,new ObjecturlStr, encoding,120000, 100); System.out.println(result);.getCacheData方法返回值与initUrlData方法返回类型一样，参数说明：data：调用initUrlData方法的实列，如果该方法是静态的，则传类的类型，如（DataCreator .class）；initUrlData：方法名称；new Objecturl