org.xml.sax.SAXParseException: src-import.0: Failed to read imported schema document 'null'

公司项目用的是ssh，最近发现每次tomcat启动的时候，控制台总是出现下面的这个异常

2015-04-10 09:13:50 [org.springframework.web.context.ContextLoader]-[INFO] - Root WebApplicationContext: initialization started
2015-04-10 09:13:50 [org.springframework.web.context.support.XmlWebApplicationContext]-[INFO] - Refreshing Root WebApplicationContext: startup date [Fri Apr 10 09:13:50 CST 2015]; root of context hierarchy
2015-04-10 09:13:50 [org.springframework.beans.factory.xml.XmlBeanDefinitionReader]-[INFO] - Loading XML bean definitions from class path resource [applicationContext.xml]
2015-04-10 09:13:50 [org.springframework.beans.factory.xml.XmlBeanDefinitionReader]-[WARN] - Ignored XML validation warning
org.xml.sax.SAXParseException: src-import.0: Failed to read imported schema document 'null'.
at org.apache.xerces.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:232)
at org.apache.xerces.util.ErrorHandlerWrapper.warning(ErrorHandlerWrapper.java:141)
at org.apache.xerces.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:358)
at org.apache.xerces.impl.xs.traversers.XSDHandler.reportSchemaWarning(XSDHandler.java:1837)
at org.apache.xerces.impl.xs.traversers.XSDHandler.getSchema(XSDHandler.java:1298)
at org.apache.xerces.impl.xs.traversers.XSDHandler.getSchema(XSDHandler.java:1240)
at org.apache.xerces.impl.xs.traversers.XSDHandler.constructTrees(XSDHandler.java:611)
at org.apache.xerces.impl.xs.traversers.XSDHandler.parseSchema(XSDHandler.java:403)
at org.apache.xerces.impl.xs.traversers.XSDHandler.parseSchema(XSDHandler.java:381)
at org.apache.xerces.impl.xs.XMLSchemaValidator.parseSchema(XMLSchemaValidator.java:2250)
at org.apache.xerces.impl.xs.XMLSchemaValidator.findSchemaGrammar(XMLSchemaValidator.java:2178)
at org.apache.xerces.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:1724)
at org.apache.xerces.impl.xs.XMLSchemaValidator.startElement(XMLSchemaValidator.java:568)
at org.apache.xerces.impl.XMLNamespaceBinder.handleStartElement(XMLNamespaceBinder.java:832)
at org.apache.xerces.impl.XMLNamespaceBinder.startElement(XMLNamespaceBinder.java:568)
at org.apache.xerces.impl.dtd.XMLDTDValidator.startElement(XMLDTDValidator.java:796)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanStartElement(XMLDocumentFragmentScannerImpl.java:752)
at org.apache.xerces.impl.XMLDocumentScannerImpl$ContentDispatcher.scanRootElementHook(XMLDocumentScannerImpl.java:927)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(XMLDocumentFragmentScannerImpl.java:1519)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:333)
at org.apache.xerces.parsers.StandardParserConfiguration.parse(StandardParserConfiguration.java:529)
at org.apache.xerces.parsers.StandardParserConfiguration.parse(StandardParserConfiguration.java:585)
at org.apache.xerces.parsers.XMLParser.parse(XMLParser.java:147)
at org.apache.xerces.parsers.DOMParser.parse(DOMParser.java:221)
at org.apache.xerces.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:201)
at org.springframework.beans.factory.xml.DefaultDocumentLoader.loadDocument(DefaultDocumentLoader.java:75)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.doLoadBeanDefinitions(XmlBeanDefinitionReader.java:388)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:334)
at org.springframework.beans.factory.xml.XmlBeanDefinitionReader.loadBeanDefinitions(XmlBeanDefinitionReader.java:302)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:174)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:209)
at org.springframework.beans.factory.support.AbstractBeanDefinitionReader.loadBeanDefinitions(AbstractBeanDefinitionReader.java:180)
at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:125)
at org.springframework.web.context.support.XmlWebApplicationContext.loadBeanDefinitions(XmlWebApplicationContext.java:94)
at org.springframework.context.support.AbstractRefreshableApplicationContext.refreshBeanFactory(AbstractRefreshableApplicationContext.java:131)
at org.springframework.context.support.AbstractApplicationContext.obtainFreshBeanFactory(AbstractApplicationContext.java:537)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:451)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:383)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:283)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:112)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4206)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4705)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:799)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:779)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:601)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1079)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:1002)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:506)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1317)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:324)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1065)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)
at org.apache.catalina.core.StandardService.start(StandardService.java:525)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:754)
at org.apache.catalina.startup.Catalina.start(Catalina.java:595)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)

出现这个异常并没有影响程序的运行，就是看着很不爽。

根据异常分析和网上查找结果表示该异常基本上确定是spring配置文件头引入xsd错误造成，即无法正确的访问到xsd文件，原因大致有三个：

一：网络异常，无法访问到配置spring的xsd文件网址

二：头文件引入的xsd文件与使用spring版本不一致

三：引入的xsd文件不存在（指向本地）

我的spring文件头如下：

<?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"
xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd">
</beans>

在我的配置中，点击每一个http链接都可以访问到xsd文件信息，并且网络正常，因此排除第一个原因。

项目中使用的是spring3.2版本，考虑到第二个原因，将配置文件做以下修改：

<?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"
xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.2.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.2.xsd">
</beans>

指定版本号之后，点击http链接同样可以根据网络访问到配置文件信息，但程序异常依然存在。

考虑到可能是网络的原因无法访问，考录将sping的xsd指定为本机文件，在spring的jar中可以找到对应的xsd文件，

修改如下：

<?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"
xsi:schemaLocation=" http://www.springframework.org/schema/beans classpath:org/springframework/beans/factory/xml/spring-beans-3.2.xsd http://www.springframework.org/schema/tx classpath:org/springframework/transaction/config/spring-tx-3.2.xsd http://www.springframework.org/schema/aop classpath:org/springframework/aop/config/spring-aop-3.2.xsd">
</beans>

问题依旧！本地文件真实存在的。

百思不得其解。

又在网上遨游了半天，无意中发现了一个博友好像因为xercesImpl.jar版本出现过这个问题，赶紧做个尝试。

果不其然，换了一个高版本的xercesImpl.jar后，异常奇迹般的消失了。

经查找发现xercesImpl.jar主要用来解析XML文件，与我的问题也刚好对应，应该就是这个jar的问题了。

至此，问题解决。