Javaweb学习笔记——Server Tomcat v9.0 Server at localhost failed to start.

  今天在写一个注册功能时遇到了如下错误：

     

    错误显示Tomcat启动不了，查看控制台的错误信息如下：

四月 21, 2017 5:56:16 下午 org.apache.tomcat.util.digester.SetPropertiesRule begin
警告: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property 'source' to 'org.eclipse.jst.jee.server:login' did not find a matching property.
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: Server version:        Apache Tomcat/9.0.0.M19
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: Server built:          Mar 27 2017 12:09:59 UTC
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: Server number:         9.0.0.0
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: OS Name:               Windows 10
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: OS Version:            10.0
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: Architecture:          amd64
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: Java Home:             H:\Java8\jre1.8.0_121
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: JVM Version:           1.8.0_121-b13
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: JVM Vendor:            Oracle Corporation
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: CATALINA_BASE:         F:\workspace\workspace-neon\.metadata\.plugins\org.eclipse.wst.server.core\tmp0
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: CATALINA_HOME:         H:\apache-tomcat-9.0.0.M19
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: Command line argument: -Dcatalina.base=F:\workspace\workspace-neon\.metadata\.plugins\org.eclipse.wst.server.core\tmp0
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: Command line argument: -Dcatalina.home=H:\apache-tomcat-9.0.0.M19
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: Command line argument: -Dwtp.deploy=F:\workspace\workspace-neon\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: Command line argument: -Djava.endorsed.dirs=H:\apache-tomcat-9.0.0.M19\endorsed
四月 21, 2017 5:56:16 下午 org.apache.catalina.startup.VersionLoggerListener log
信息: Command line argument: -Dfile.encoding=GBK
四月 21, 2017 5:56:16 下午 org.apache.catalina.core.AprLifecycleListener lifecycleEvent
信息: The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: H:\Java8\jre1.8.0_121\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;H:/Java8/jre1.8.0_121/bin/server;H:/Java8/jre1.8.0_121/bin;H:/Java8/jre1.8.0_121/lib/amd64;C:\ProgramData\Oracle\Java\javapath;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;H:\Java8\jdk1.8.0_121\bin;H:\Java8\jdk1.8.0_121\jre\bin;H:\Android\sdk\tools;H:\Android\sdk\platform-tools;H:\Microsoft SQL Server2008\x86\100\Tools\Binn\;H:\Microsoft SQL Server2008\100\Tools\Binn\;H:\Microsoft SQL Server2008\100\DTS\Binn\;H:\Microsoft SQL Server2008\x86\100\Tools\Binn\VSShell\Common7\IDE\;H:\Microsoft SQL Server2008\x86\100\DTS\Binn\;C:\Users\41823\AppData\Local\Microsoft\WindowsApps;;H:\Microsoft VS Code\bin;H:\Eclipse\eclipse-java-neon\eclipse;;.
四月 21, 2017 5:56:16 下午 org.apache.coyote.AbstractProtocol init
信息: Initializing ProtocolHandler ["http-nio-8080"]
四月 21, 2017 5:56:17 下午 org.apache.tomcat.util.net.NioSelectorPool getSharedSelector
信息: Using a shared selector for servlet write/read
四月 21, 2017 5:56:17 下午 org.apache.coyote.AbstractProtocol init
信息: Initializing ProtocolHandler ["ajp-nio-8009"]
四月 21, 2017 5:56:17 下午 org.apache.tomcat.util.net.NioSelectorPool getSharedSelector
信息: Using a shared selector for servlet write/read
四月 21, 2017 5:56:17 下午 org.apache.catalina.startup.Catalina load
信息: Initialization processed in 1310 ms
四月 21, 2017 5:56:17 下午 org.apache.catalina.core.StandardService startInternal
信息: Starting service Catalina
四月 21, 2017 5:56:17 下午 org.apache.catalina.core.StandardEngine startInternal
信息: Starting Servlet Engine: Apache Tomcat/9.0.0.M19
四月 21, 2017 5:56:18 下午 org.apache.jasper.servlet.TldScanner scanJars
信息: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
四月 21, 2017 5:56:18 下午 org.apache.catalina.core.ContainerBase startInternal
严重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/login]]
at java.util.concurrent.FutureTask.report(Unknown Source)
at java.util.concurrent.FutureTask.get(Unknown Source)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:959)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:872)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1439)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1429)
at java.util.concurrent.FutureTask.run(Unknown Source)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.util.concurrent.AbstractExecutorService.submit(Unknown Source)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:953)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:422)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:793)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.startup.Catalina.start(Catalina.java:655)
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:355)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:495)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/login]]
at org.apache.catalina.util.LifecycleBase.handleSubClassException(LifecycleBase.java:441)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:198)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1439)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1429)
at java.util.concurrent.FutureTask.run(Unknown Source)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.util.concurrent.AbstractExecutorService.submit(Unknown Source)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:953)
... 21 more
Caused by: java.lang.IllegalArgumentException: The servlets named [Signup] and [myservlet.Signup] are both mapped to the url-pattern [/Signup] which is not permitted
at org.apache.tomcat.util.descriptor.web.WebXml.addServletMappingDecoded(WebXml.java:328)
at org.apache.tomcat.util.descriptor.web.WebXml.addServletMapping(WebXml.java:321)
at org.apache.catalina.startup.ContextConfig.processAnnotationWebServlet(ContextConfig.java:2391)
at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:2068)
at org.apache.catalina.startup.ContextConfig.processAnnotationsWebResource(ContextConfig.java:1954)
at org.apache.catalina.startup.ContextConfig.processAnnotationsWebResource(ContextConfig.java:1948)
at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1153)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:775)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:299)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:123)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5095)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
... 27 more


四月 21, 2017 5:56:18 下午 org.apache.catalina.core.ContainerBase startInternal
严重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: A child container failed during start
at java.util.concurrent.FutureTask.report(Unknown Source)
at java.util.concurrent.FutureTask.get(Unknown Source)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:959)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:422)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:793)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.startup.Catalina.start(Catalina.java:655)
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:355)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:495)
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:968)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:872)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1439)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1429)
at java.util.concurrent.FutureTask.run(Unknown Source)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.util.concurrent.AbstractExecutorService.submit(Unknown Source)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:953)
... 13 more


四月 21, 2017 5:56:18 下午 org.apache.catalina.startup.Catalina start
严重: The required Server component failed to start so Tomcat is unable to start.
org.apache.catalina.LifecycleException: A child container failed during start
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:968)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:422)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:793)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.startup.Catalina.start(Catalina.java:655)
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:355)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:495)


四月 21, 2017 5:56:18 下午 org.apache.coyote.AbstractProtocol pause
信息: Pausing ProtocolHandler ["http-nio-8080"]
四月 21, 2017 5:56:18 下午 org.apache.coyote.AbstractProtocol pause
信息: Pausing ProtocolHandler ["ajp-nio-8009"]
四月 21, 2017 5:56:18 下午 org.apache.catalina.core.StandardService stopInternal
信息: Stopping service Catalina
四月 21, 2017 5:56:18 下午 org.apache.coyote.AbstractProtocol destroy
信息: Destroying ProtocolHandler ["http-nio-8080"]
四月 21, 2017 5:56:18 下午 org.apache.coyote.AbstractProtocol destroy
信息: Destroying ProtocolHandler ["ajp-nio-8009"]

    查看错误信息时我们主要查看caused by里的内容，经过分析，主要原因是这一块出了问题：

    这里提示我web.xml里的url-pattern[/Signup]被我在web.xml里命名的Signup和我类包里的Signup同时匹配，这是不允许的。大家看我web.xml里的内容：

    我的url-pattern这样的命名方式是不允许的，同样取名包名+类名（/myservlet/servlet）这样的格式也是不可以的，因为这样会引起混淆。这里我们把url-pattern里的路径改成/servlet/Signup就可以了，这个名字随便取的。

这是更改后的web.xml文件：

这样就可以运行了。