（1）Shiro筆記-整合Ehcache時缺少默認cache配置異常解決

在使用Ehcache配置shiro cacheManager時遇到了如下異常，異常全文：

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'shiroFilter' defined in URL [file:/D:/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp2/wtpwebapps/SpringMVCTest/WEB-INF/classes/config/spring-shiro-web.xml]: Cannot resolve reference to bean 'securityManager' while setting bean property 'securityManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'securityManager' defined in URL [file:/D:/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp2/wtpwebapps/SpringMVCTest/WEB-INF/classes/config/spring-shiro-web.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'cacheManager' threw exception; nested exception is org.apache.shiro.cache.CacheException: net.sf.ehcache.CacheException: Caches cannot be added by name when default cache config is not specified in the config. Please add a default cache config in the configuration.
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:359)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1531)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1276)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:553)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.registerBeanPostProcessors(PostProcessorRegistrationDelegate.java:235)
    at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:703)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:528)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:443)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:325)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4797)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5221)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
    at java.util.concurrent.FutureTask.run(FutureTask.java:262)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)

主要異常信息如下

Caches cannot be added by name when default cache config is not specified in the config. Please add a default cache config in the configuration.

其實異常原因也挺容易明白的，就是缺少了一個默認cache配置，在Ehcache官網上也有相應的說明：
http://www.ehcache.org/documentation/2.8/faq.html
What does the following error mean? “Caches cannot be added by name when default cache config is not specified in the config. Please add a default cache config in the configuration.”
From Ehcache 2.4, the defaultCache is optional. When you try to programmatically add a cache by name, CacheManager.add(String name), a default cache is expected to exist in the CacheManager configuration. To fix this error, add a defaultCache to the CacheManager’s configuration.

很明顯，在2.4版本之後，配置Ehcache文件時，開始需要添加一個默認cache配置。問題明白了，就好解決了，在Ehcache配置文件中添加如下代碼即可：

<defaultCache    
    maxElementsInMemory="10000"    
    maxElementsOnDisk="0"    
    eternal="true"    
    overflowToDisk="true"    
    diskPersistent="false"    
    timeToIdleSeconds="0"    
    timeToLiveSeconds="0"    
    diskSpoolBufferSizeMB="50"    
    diskExpiryThreadIntervalSeconds="120"    
    memoryStoreEvictionPolicy="LFU"    
    />