由于系统需求需
要对各个接口进行key-value缓存(以参数为key,返回的对象为value),当然对于这种情况首先考虑到的是使用aop,前段时间看过
aspectj的一些介绍,借此机会正好加以应用和体会一下,aspectj是AOP最早成熟的java实现,它稍微扩展了一下java语言,增加了一些
keyword等,具体的aspectj的基本语法见[ur=http://today.java.net/pub/a/today/2003/12
/26/ch3AspectJSyntaxBasics.html]这里[/url],进行缓存的框架使用较成熟的ehcache.
下面开始进行配置
首先是ehcache的配置文件
<?xml version="1.0" encoding="UTF-8"?>
<ehcache>
<diskStore path="/home/workspace/gzshine/trunk/ehcache"/>
<cache name="DEFAULT_CACHE"
maxElementsInMemory="10000"
eternal="false"
timeToIdleSeconds="3600"
timeToLiveSeconds="3600"
overflowToDisk="true"/>
</ehcache>
这个的DEFAULT_CACHE是默认配置,最大的缓存数为10000,时间为一个小时
接下来的是spring下的配置
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-2.5.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd">
<!-- ############## aspectj 4 ehcache ############# -->
<aop:aspectj-autoproxy proxy-target-class="true"/>
<bean id = "methodCacheAspectJ" class="com.***.shine.aspectj.MethodCacheAspectJ" >
<property name="cache">
<ref local="methodCache" />
</property>
</bean>
<bean id="cacheManager"
class="org.springframework.cache.ehcache.EhCacheManagerFactoryBean">
<property name="configLocation">
<value>classpath:ehcache.xml</value>
</property>
</bean>
<!-- 定义ehCache的工厂，并设置所使用的Cache name -->
<bean id="methodCache"
class="org.springframework.cache.ehcache.EhCacheFactoryBean">
<property name="cacheManager">
<ref local="cacheManager" />
</property>
<property name="cacheName">
<value>DEFAULT_CACHE</value>
</property>
</bean>
<aop:aspectj-autoproxy proxy-target-class="true"/>
是为aspectj在所有class下开启自动动态代理
<bean id="cacheManager">指定刚刚的ehcache配置文件
接下来编写一个自定义的annotation
package com.***.shine.cache;
import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
@Target({ElementType.METHOD,ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface MethodCache {
int second() default 0;
}
<bean id = "methodCacheAspectJ">是一个aspectj进行Pointcuts和Advice的类需注入methodCache
package com.***.shine.aspectj;
@Aspect
public class MethodCacheAspectJ {
Log logger = LogFactory.getLog(MethodCacheAspectJ.class);
private Cache cache;
/**
* 设置缓存名
*/
public void setCache(Cache cache) {
this.cache = cache;
}
@Pointcut("@annotation(com.***.shine.cache.MethodCache)")
public void methodCachePointcut(){
}
@Around("methodCachePointcut()")
public Object methodCacheHold(ProceedingJoinPoint joinPoint) throws Throwable{
String targetName = joinPoint.getTarget().getClass().getName();
String methodName = joinPoint.getSignature().getName();
Object[] arguments = joinPoint.getArgs();
Object result = null;
String cacheKey = getCacheKey(targetName, methodName, arguments);
Element element = cache.get(cacheKey);
if (element == null) {
try{
result = joinPoint.proceed();
}catch(Exception e){
logger.info(e);
}
if(result!=null){
try{
element = new Element(cacheKey, (Serializable) result);
Class targetClass = Class.forName(targetName);
Method[] method = targetClass.getMethods();
int second = 0;
for(Method m:method){
if (m.getName().equals(methodName)) {
Class[] tmpCs = m.getParameterTypes();
if(tmpCs.length==arguments.length){
MethodCache methodCache = m.getAnnotation(MethodCache.class);
second = methodCache.second();
break;
}
}
}
if(second>0){ // annotation没有设second值则使用ehcache.xml中自定义值
element.setTimeToIdle(second);
element.setTimeToLive(second);
}
cache.put(element);
}catch(Exception e){
logger.info("!!!!!!!!!"+cacheKey+"!!!!!!!!!未能执行方法缓存"+e);
}
}
}
return element.getValue();
}
private String getCacheKey(String targetName, String methodName,
Object[] arguments) {
StringBuffer sb = new StringBuffer();
sb.append(targetName).append(".").append(methodName);
if ((arguments != null) && (arguments.length != 0)) {
for (int i = 0; i < arguments.length; i++) {
if (arguments[i] instanceof Date) {
sb.append(".").append(
DateUtil.datetoString((Date) arguments[i]));
} else {
sb.append(".").append(arguments[i]);
}
}
}
return sb.toString();
}
}
@Pointcut("@annotation(com.netease.shine.cache.MethodCache)")
对有应用com.netease.shine.cache.MethodCache进行注解的方法进行横切面拦截
@Around("methodCachePointcut()")
并在Advice中处理这个Pointcut,这里的的Advice使用的是Around(环绕通知)
String cacheKey = getCacheKey(targetName, methodName, arguments);
接下来使用类型,方法名,参数为key进入缓存处理
Element element = cache.get(cacheKey);
当然如果在cache队列中取得非null对象则直接返回该对象
MethodCache methodCache = m.getAnnotation(MethodCache.class);
second = methodCache.second();
取得second的值(缓存的时间,如在@annotation中无重写只为int second() default 0)
element.setTimeToIdle(second);
element.setTimeToLive(second);
如果非零则重新设置缓存时间
@MethodCache(second=300)
public List<Sort> getSort(int type,int parentid){
System.out.println("!!!!!!!!!!!!!没缓存到");
Row row = new Row();
row.put("type", type);
row.put("parentid", parentid);
return (List<Sort>)gz_Template.queryForList("sort.getSort", row);
}
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陈于喆
Mail: chenyz@corp.netease.com