Could not resolve placeholder 'jdbc.username' in string value "${jdbc.username}"

1、错误描述

严重: Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
org.springframework.beans.factory.BeanDefinitionStoreException: Invalid bean definition with name 'dataSource' defined in file [E:\Eclipse\workspace\AMP\WebContent\WEB-INF\classes\spring\applicationContext.xml]: Could not resolve placeholder 'jdbc.username' in string value "${jdbc.username}"; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'jdbc.username' in string value "${jdbc.username}"
	at org.springframework.beans.factory.config.PlaceholderConfigurerSupport.doProcessProperties(PlaceholderConfigurerSupport.java:211)
	at org.springframework.beans.factory.config.PropertyPlaceholderConfigurer.processProperties(PropertyPlaceholderConfigurer.java:223)
	at org.springframework.beans.factory.config.PropertyResourceConfigurer.postProcessBeanFactory(PropertyResourceConfigurer.java:86)
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:265)
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:162)
	at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:609)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:464)
	at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
	at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
	at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
	at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4992)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5490)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1575)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1565)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: Could not resolve placeholder 'jdbc.username' in string value "${jdbc.username}"
	at org.springframework.util.PropertyPlaceholderHelper.parseStringValue(PropertyPlaceholderHelper.java:174)
	at org.springframework.util.PropertyPlaceholderHelper.replacePlaceholders(PropertyPlaceholderHelper.java:126)
	at org.springframework.beans.factory.config.PropertyPlaceholderConfigurer$PlaceholderResolvingStringValueResolver.resolveStringValue(PropertyPlaceholderConfigurer.java:259)
	at org.springframework.beans.factory.config.BeanDefinitionVisitor.resolveStringValue(BeanDefinitionVisitor.java:282)
	at org.springframework.beans.factory.config.BeanDefinitionVisitor.resolveValue(BeanDefinitionVisitor.java:204)
	at org.springframework.beans.factory.config.BeanDefinitionVisitor.visitPropertyValues(BeanDefinitionVisitor.java:141)
	at org.springframework.beans.factory.config.BeanDefinitionVisitor.visitBeanDefinition(BeanDefinitionVisitor.java:82)
	at org.springframework.beans.factory.config.PlaceholderConfigurerSupport.doProcessProperties(PlaceholderConfigurerSupport.java:208)
	... 18 more

十月 19, 2015 10:05:44 上午 org.apache.catalina.core.StandardContext startInternal
严重: Error listenerStart

2、错误原因

     数据库配置文件中有个属性jdbc.username，但是修改的过程中将其注释掉了

3、解决办法

     将jdbc.username解注，重启服务器Tomcat