eclipse+tomcat开发servlet的问题

[hyh_tyy]

在eclipse下建立了一个Tomcat Project，然后在这个Project下写了一个servlet程序，并在Project的WEB-INF目录下建立了一个web.xml配置我的这个servlet，程序完成后运行很正常，当时也就没有再理会，过了几天以后再运行的时候就出现问题了，首先用eclipse启动Tomcat的时候console会提示下面这样的信息：
- Initializing Coyote HTTP/1.1 on http-8080
- Initialization processed in 3595 ms
- Starting service Catalina
- Starting Servlet Engine: Apache Tomcat/5.5.7
- XML validation disabled
- Parse Fatal Error at line 1 column 3: The processing instruction must begin with the name of the target.
org.xml.sax.SAXParseException: The processing instruction must begin with the name of the target.
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(Unknown Source)
at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLScanner.scanPI(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDispatcher.dispatch(Unknown Source)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(Unknown Source)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1561)
at org.apache.catalina.startup.ContextConfig.applicationWebConfig(ContextConfig.java:302)
at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:959)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:249)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4020)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1011)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:718)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1011)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:440)
at org.apache.catalina.core.StandardService.start(StandardService.java:450)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:683)
at org.apache.catalina.startup.Catalina.start(Catalina.java:537)
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:271)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:409)
- Parse error in application web.xml
org.xml.sax.SAXParseException: The processing instruction must begin with the name of the target.
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(Unknown Source)
at org.apache.tomcat.util.digester.Digester.parse(Digester.java:1561)
at org.apache.catalina.startup.ContextConfig.applicationWebConfig(ContextConfig.java:302)
at org.apache.catalina.startup.ContextConfig.start(ContextConfig.java:959)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:249)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4020)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1011)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:718)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1011)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:440)
at org.apache.catalina.core.StandardService.start(StandardService.java:450)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:683)
at org.apache.catalina.startup.Catalina.start(Catalina.java:537)
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:271)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:409)
- Occurred at line 1 column 3
- Marking this application unavailable due to previous error(s)
- Error getConfigured
- Context startup failed due to previous errors
- Unable to find config file. Creating new servlet engine config file: /WEB-INF/server-config.wsdd
- org.apache.webapp.balancer.BalancerFilter: init(): ruleChain: [org.apache.webapp.balancer.RuleChain: [org.apache.webapp.balancer.rules.URLStringMatchRule: Target string: News / Redirect URL: http://www.cnn.com], [org.apache.webapp.balancer.rules.RequestParameterRule: Target param name: paramName / Target param value: paramValue / Redirect URL: http://www.yahoo.com], [org.apache.webapp.balancer.rules.AcceptEverythingRule: Redirect URL: http://jakarta.apache.org]]
- ContextListener: contextInitialized()
- SessionListener: contextInitialized()
- ContextListener: contextInitialized()
- SessionListener: contextInitialized()
- Starting Coyote HTTP/1.1 on http-8080
- JK2: ajp13 listening on /0.0.0.0:8009
- Jk running ID=0 time=0/290 config=null
- Find registry server-registry.xml at classpath resource
- Server startup in 13209 ms

然后访问我的servlet则不能正常运行了，控制台提示这样的信息：
- HTMLManager: init: Associated with Deployer 'Catalina:type=Deployer,host=localhost'
- HTMLManager: init: Global resources are available
- HTMLManager: list: Listing contexts for virtual host 'localhost'
- HTMLManager: list: Listing contexts for virtual host 'localhost'

还请高手指教。谢谢先