包含 Tomcat 7（当 servlet 项目时）不会在 45 秒内启动...并且增加超时并不能解决问题

Question

当尝试运行 Web 应用程序（带有 servlet）时，Tomcat 7 未启动。当我只有 html 页面时，服务器运行良好。但是当我尝试添加 servlet 并将其添加到 tomcat 时。然后服务器不启动启动并给出错误“Tomcat 7 在 45 秒内未启动”。我增加了超时但没有任何反应。请帮我解决这个问题

控制台说：

"23 Jan, 2012 1:43:44 PM org.apache.catalina.core.AprLifecycleListener init
INFO: The APR based Apache Tomcat Native library which allows optimal performance in                  production environments was not found on the java.library.path: C:\Program Files (x86)\Java\jdk1.7.0\bin;.;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:/Program Files/Java/jdk1.6.0_23/jre/bin/server;C:/Program Files/Java/jdk1.6.0_23/jre/bin;C:/Program Files/Java/jdk1.6.0_23/jre/lib/amd64;C:\Program Files (x86)\Java\jdk1.7.0\jre\bin;F:\SOFTWARES\Eclipse Indigo\eclipse;
23 Jan, 2012 1:43:44 PM org.apache.tomcat.util.digester.SetPropertiesRule begin
WARNING: [SetPropertiesRule]{Server/Service/Engine/Host/Context} Setting property     'source' to 'org.eclipse.jst.jee.server:Basic' did not find a matching property.
23 Jan, 2012 1:43:44 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["http-bio-80"]
23 Jan, 2012 1:43:44 PM org.apache.coyote.AbstractProtocol init
INFO: Initializing ProtocolHandler ["ajp-bio-9999"]
23 Jan, 2012 1:43:44 PM org.apache.catalina.startup.Catalina load
INFO: Initialization processed in 717 ms
23 Jan, 2012 1:43:44 PM org.apache.catalina.core.StandardService startInternal
INFO: Starting service Catalina
23 Jan, 2012 1:43:44 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/7.0.23
23 Jan, 2012 1:43:45 PM org.apache.catalina.core.ContainerBase startInternal
SEVERE: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component     [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Basic]]
at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:252)
at java.util.concurrent.FutureTask.get(FutureTask.java:111)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1100)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:782)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1525)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1515)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:674)
    Caused by: org.apache.catalina.LifecycleException: Failed to start component     [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Basic]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
    ... 7 more
    Caused by: java.lang.UnsupportedClassVersionError: Simple : Unsupported major.minor version 51.0 (unable to load class Simple)
at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2827)
at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1160)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1655)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1533)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationServletAnnotations(WebAnnotationSet.java:108)
at org.apache.catalina.startup.WebAnnotationSet.loadApplicationAnnotations(WebAnnotationSet.java:58)
at org.apache.catalina.startup.ContextConfig.applicationAnnotationsConfig(ContextConfig.java:338)
at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:831)
at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:302)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5148)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 7 more
23 Jan, 2012 1:43:45 PM org.apache.catalina.core.ContainerBase startInternal
SEVERE: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to     start component [StandardEngine[Catalina].StandardHost[localhost]]
at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:252)
at java.util.concurrent.FutureTask.get(FutureTask.java:111)
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1100)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:291)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:727)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.startup.Catalina.start(Catalina.java:624)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:623)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:322)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:450)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1525)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1515)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:674)
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1108)
at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:782)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 7 more
23 Jan, 2012 1:43:45 PM org.apache.catalina.startup.Catalina start
SEVERE: Catalina.start: 
org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8000]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.startup.Catalina.start(Catalina.java:624)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:623)
at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:322)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:450)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:727)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 7 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component         [StandardEngine[Catalina]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 9 more
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1108)
at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:291)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
... 11 more
23 Jan, 2012 1:43:45 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 313 ms "    '

Answer 1

如果你只是将异常原因的错误信息复制到Google中，你就会发现问题所在。 “不支持的major.minor版本51.0”意味着您使用JDK7编译了类，但尝试使用早期版本的JDK或JRE来部署和运行它。使用 JDK7 启动 Tomcat，或者更改用于编译类的 JDK。

旁注：您的类似乎被命名为 Simple 并且位于默认包中。这是一种不好的做法，会导致各种问题。始终将您的课程放在包中。

Answer 2

在 Eclipse 中的 Servers 下的 Package Explorer 中检查文件servers.xml 中的配置。
当您在设计模式下打开此文件时，您可以看到不同的上下文配置。
对于您的开始，应该有一个条目。检查此上下文条目：docBase、路径和源应引用您的项目。