• Server Tomcat v7.0 Server at localhost failed to start.错误可能原因之一


    故事由来:

      学Servlet中,突然发现启动Tomcat时出现这个问题

    故事梗概:

      学习servlet尽然能碰到服务器起不来的,百思不得其解,然后我百度,我FQgoogle,找stackoverflow。找到了不少答案,比如stackoverflow给出说是在

    <workspace-directory>.metadata.pluginsorg.eclipse.core.resources
    

      中有个.snap文件删掉,就可解决这个问题,我试了不行。stackoverflow的链接如下:http://stackoverflow.com/questions/13244233/server-tomcat-v7-0-server-at-localhost-failed-to-start-without-stack-trace-whi

    百度下,Myexception网给出答案是1、端口被占用,2、启动时间不够,3、eclipse引发的问题,4、重新启动电脑(最笨的办法,如果不停的出现,不停的重起会烦死的。)。下面是原文链接。这答案给的没有一个是我要的,所以,以后还是尽量谷歌,百度感觉真心不靠谱。

    故事真相:

      在eclipse这个强大的软件中,我们省略很多手动写代码的时间,过程如下:

    在上图中点击finish后就生成下面的代码。

    比如在eclipse中,我们建一个新的 servlet文件后,代码中会生成如下一大块代码。

     1 import java.io.IOException;
     2 import javax.servlet.ServletException;
     3 import javax.servlet.annotation.WebServlet;
     4 import javax.servlet.http.HttpServlet;
     5 import javax.servlet.http.HttpServletRequest;
     6 import javax.servlet.http.HttpServletResponse;
     7 
     8 /**
     9  * Servlet implementation class ServletDemo
    10  */
    11 @WebServlet("/ServletDemo")
    12 public class ServletDemo extends HttpServlet {
    13     private static final long serialVersionUID = 1L;
    14        
    15     /**
    16      * @see HttpServlet#HttpServlet()
    17      */
    18     public ServletDemo() {
    19         super();
    20         // TODO Auto-generated constructor stub
    21     }
    22 
    23     /**
    24      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
    25      */
    26     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    27         // TODO Auto-generated method stub
    28         response.getWriter().append("Served at: ").append(request.getContextPath());
    29     }
    30 
    31     /**
    32      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
    33      */
    34     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    35         // TODO Auto-generated method stub
    36         doGet(request, response);
    37     }
    38 
    39 }

    而这里面,留意下有个注解

    @WebServlet("/ServletDemo")

    这个注解是eclipse帮我们生成好的,而问题恰恰就出在这。我们知道,每次我们新建一个servlet后会在web.xml文件中配置映射关系,这样才能在浏览器敲入一个地址后,地址发来的请求能让服务器接收到请求并将该请求交给指定的Servlet去处理。web.xml的作用就在此,它的代码如下:

    <?xml version="1.0" encoding="UTF-8"?>
    <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0"> <servlet> <servlet-name>ServletDemo</servlet-name> <servlet-class>com.vivizhang.servlet.HelloWorldServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>ServletDemo</servlet-name> <url-pattern>/HelloServlet</url-pattern> </servlet-mapping> </web-app>

    所以问题的真相就是配置自动生成的注解冲突了,导致如下的错误(截取):

     A child container failed during start
    java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/ServletDemo]]
        at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:252)
        at java.util.concurrent.FutureTask.get(FutureTask.java:111)
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1120)
        at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:819)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1572)
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1562)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
        at java.util.concurrent.FutureTask.run(FutureTask.java:166)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:722)
    Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/HelloServlet]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
        ... 7 more
    Caused by: java.lang.IllegalArgumentException: The servlets named [ServletDemo] and [com.vivizhang.servlet.ServletDemo] are both mapped to the url-pattern [/ServletDemo] which is not permitted
        at org.apache.catalina.deploy.WebXml.addServletMapping(WebXml.java:293)
        at org.apache.catalina.startup.ContextConfig.processAnnotationWebServlet(ContextConfig.java:2462)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:2137)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:2098)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:2090)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:2090)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:2090)
        at org.apache.catalina.startup.ContextConfig.processAnnotationsFile(ContextConfig.java:2090)
        at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1304)
        at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:889)
        at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:386)
        at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
        at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5472)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
        ... 7 more
    
    九月 18, 2016 4:40:37 下午 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$Sync.innerGet(FutureTask.java:252)
        at java.util.concurrent.FutureTask.get(FutureTask.java:111)
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1120)
        at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
        at org.apache.catalina.core.StandardService.startInternal(StandardService.java:444)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
        at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:738)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
        at org.apache.catalina.startup.Catalina.start(Catalina.java:693)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:294)
        at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:428)
    Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1572)
        at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1562)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
        at java.util.concurrent.FutureTask.run(FutureTask.java:166)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:722)
    Caused by: org.apache.catalina.LifecycleException: A child container failed during start
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1128)
        at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:819)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
        ... 7 more
    
    九月 18, 2016 4:40:37 下午 org.apache.catalina.startup.Catalina start
    SEVERE: The required Server component failed to start so Tomcat is unable to start.
    org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8006]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
        at org.apache.catalina.startup.Catalina.start(Catalina.java:693)
        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:601)
        at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:294)
        at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:428)
    Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
        at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:738)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
        ... 7 more
    Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153)
        at org.apache.catalina.core.StandardService.startInternal(StandardService.java:444)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
        ... 9 more
    Caused by: org.apache.catalina.LifecycleException: A child container failed during start
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1128)
        at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147)
        ... 11 more

    这里的问题出在:

    The servlets named [ServletDemo] and [com.vivizhang.servlet.ServletDemo] are both mapped to the url-pattern [/ServletDemo] which is not permitted

    故事解决办法:

      可以选择删除web.xml中的映射,也可以选择将自动生成的注解注释掉,这样就不会有冲突了,二者选其一留下即可。

    故事后续:

      如果在其他问题都没出错的情况下,可能就是xml文件和注解出现了冲突,当然,出现这个问题的原因不止这一个,会有其他很多原因,去google吧,希望我的文章能帮助你解决实际的问题。

    不畏浮云遮望眼,只缘身在此山中,安静提高自己,功过留给别人去说。
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  • 原文地址:https://www.cnblogs.com/vivizhang/p/vivizhang.html
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