關於報錯“More than one fragment with the name [spring_web] was found. This is not legal ...”的解決辦法

最近在搭建一個spring mvc 項目時遇到“More than one fragment with the name [spring_web] was found. This is not legal ...”報錯，詳細的日志信息如下：

……
五月 08, 2019 11:49:52 下午 org.apache.catalina.core.ContainerBase startInternal
嚴重: A child container failed during start
java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Chapter14]]
    at java.util.concurrent.FutureTask.report(FutureTask.java:122)
    at java.util.concurrent.FutureTask.get(FutureTask.java:192)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:942)
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:872)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1423)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1413)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Chapter14]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    ... 6 more
Caused by: java.lang.IllegalArgumentException: More than one fragment with the name [spring_web] was found. This is not legal with relative ordering. See section 8.2.2 2c of the Servlet specification for details. Consider using absolute ordering.
    at org.apache.tomcat.util.descriptor.web.WebXml.orderWebFragments(WebXml.java:2200)
    at org.apache.tomcat.util.descriptor.web.WebXml.orderWebFragments(WebXml.java:2159)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1124)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:769)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:299)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:94)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5134)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 6 more

五月 08, 2019 11:49:52 下午 org.apache.catalina.core.ContainerBase startInternal
嚴重: 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.report(FutureTask.java:122)
    at java.util.concurrent.FutureTask.get(FutureTask.java:192)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:942)
    at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardService.startInternal(StandardService.java:422)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:793)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:688)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:353)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:493)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1423)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1413)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:953)
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:872)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 6 more
Caused by: java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Chapter14]]
    at java.util.concurrent.FutureTask.report(FutureTask.java:122)
    at java.util.concurrent.FutureTask.get(FutureTask.java:192)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:942)
    ... 8 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Chapter14]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    ... 6 more
Caused by: java.lang.IllegalArgumentException: More than one fragment with the name [spring_web] was found. This is not legal with relative ordering. See section 8.2.2 2c of the Servlet specification for details. Consider using absolute ordering.
    at org.apache.tomcat.util.descriptor.web.WebXml.orderWebFragments(WebXml.java:2200)
    at org.apache.tomcat.util.descriptor.web.WebXml.orderWebFragments(WebXml.java:2159)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1124)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:769)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:299)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:94)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5134)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 6 more

五月 08, 2019 11:49:52 下午 org.apache.catalina.startup.Catalina start
嚴重: The required Server component failed to start so Tomcat is unable to start.
org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8005]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:688)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:353)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:493)
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:793)
    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:167)
    at org.apache.catalina.core.StandardService.startInternal(StandardService.java:422)
    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:953)
    at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 11 more
Caused by: java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
    at java.util.concurrent.FutureTask.report(FutureTask.java:122)
    at java.util.concurrent.FutureTask.get(FutureTask.java:192)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:942)
    ... 13 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1423)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1413)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:953)
    at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:872)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 6 more
Caused by: java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Chapter14]]
    at java.util.concurrent.FutureTask.report(FutureTask.java:122)
    at java.util.concurrent.FutureTask.get(FutureTask.java:192)
    at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:942)
    ... 8 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Chapter14]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    ... 6 more
Caused by: java.lang.IllegalArgumentException: More than one fragment with the name [spring_web] was found. This is not legal with relative ordering. See section 8.2.2 2c of the Servlet specification for details. Consider using absolute ordering.
    at org.apache.tomcat.util.descriptor.web.WebXml.orderWebFragments(WebXml.java:2200)
    at org.apache.tomcat.util.descriptor.web.WebXml.orderWebFragments(WebXml.java:2159)
    at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1124)
    at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:769)
    at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:299)
    at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:94)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5134)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
    ... 6 more

五月 08, 2019 11:49:52 下午 org.apache.coyote.AbstractProtocol pause
信息: Pausing ProtocolHandler ["http-nio-8080"]
五月 08, 2019 11:49:52 下午 org.apache.coyote.AbstractProtocol pause
信息: Pausing ProtocolHandler ["ajp-nio-8009"]
五月 08, 2019 11:49:52 下午 org.apache.catalina.core.StandardService stopInternal
信息: Stopping service [Catalina]
五月 08, 2019 11:49:52 下午 org.apache.coyote.AbstractProtocol destroy
信息: Destroying ProtocolHandler ["http-nio-8080"]
五月 08, 2019 11:49:52 下午 org.apache.coyote.AbstractProtocol destroy
信息: Destroying ProtocolHandler ["ajp-nio-8009"]

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 添加代碼<absolute-ording />

這是多個片段重復的原因

來源：CSDN
原文：https://blog.csdn.net/PursueExcellence/article/details/89981690
版權聲明：本文為博主原創文章，轉載請附上博文鏈接！

 

<absolute-ording />這句話是什么意思呢，表示絕對順序

Web框架的可插入性 
我們前面說過了Servlet3.0的改進之一就是使得我們能夠將框架和庫插入到web應用程序中。這種可插入性減少了配置，並且提高了web應用程序的模塊化。Servlet3.0是通過web模塊布署描述片段（簡稱web片段）來實現插入性的。 
一個web片段就是web.xml文件的一部分，被包含在框架特定的Jar包的META-INF目錄中。Web片段使得該框架組件邏輯上就是web應用程序的一部分，不需要編輯web布署描述文件。 
Web片段中使用的元素和布署文件中使用的元素基本相同，除了根元素不一樣。Web片段的根元素是<web-fragment>,而且文件名必須叫做web-fragment.xml。容器只會在放在WEB-INF\lib目錄下的Jar包中查找web-fragment.xml文件。如果這些Jar包含有web-fragment.xml文件，容器就會裝載需要的類來處理他們。 
在web.xml中，我們要求Servlet的name必須唯一。同樣的，在web.xml和所有的web片段中，Servlet的name也必須唯一。 
下面就是一個web-fragment的例子： 
web-fragment.xml

1. <web-fragment>

2. <servlet>

3. <servlet-name>ControllerServlet</servlet-name>

4. <servlet-class>com.app.control.ControllerServlet</servlet-class>

5. </servlet>

6. <listener>

7. <listener-class>com.listener.AppServletContextListener</listener-class>

8. </listener>

9. </web-fragment>

復制代碼

框架的Jar包是放在WEB-INF\lib目錄下的，但是Servlet3.0提供兩種方法指定多個web片段之間的順序： 
   1. 絕對順序 
   2. 相對順序 
我們通過web.xml文件中的<absolute-ordering>元素來指定絕對順序。這個元素有之元素name，name的值是各個web片段的name元素的值。這樣就指定了web片段的順序。如果多個web片段有相同的名字，容器會忽略后出現的web片段。下面是一個指定絕對順序的例子： 
web.xml

1. <web-app>

2. <name>DemoApp</name>

3. <absolute-ordering>

4. <name>WebFragment1</name>

5. <name>WebFragment2</name>

6. </absolute-ordering>

7. ...

8. </web-app>

復制代碼

相對順序通過web-fragment.xml中的<ordering>元素來確定。Web片段的順序由<ordering>的子元素<before>,<after>和<others>來決定。當前的web片段會放在所有的<before>元素中的片段之前。同樣的，會放在所有的<after>元素中的片段之后。<others>用來代替所有的其他片段。注意只有當web.xml中沒有<absolute-ordering>時，容器才會使用web片段中定義的相對順序。 
下面是一個幫助理解相對順序的例子： 
web-fragment.xml

1. <web-fragment>

2. <name>WebFragment1</name>

3. <ordering><after>WebFragment2</after></ordering>

4. ...

5. </web-fragment>

復制代碼

web-fragment.xml

1. <web-fragment>

2. <name>WebFragment2</name>

3. ..

4. </web-fragment>

復制代碼

web-fragment.xml

1. <web-fragment>

2. <name>WebFragment3</name>

3. <ordering><before><others/></before></ordering>

復制代碼

.. 
</web-fragment> 
這些文件將會按照下面的順序被處理： 
   1. WebFragment3 
   2. WebFragment2 
   3. WebFragment1 
包含WebFragment3的Jar文件被最先處理，包含WebFragment2的文件被第二個處理，包含WebFragment1的文件被最后處理。 
如果既沒有定義絕對順序，也沒有定義相對順序，那么容器就認為所有的web片段間沒有順序上的依賴關系。 
Servlet中的異步處理 
很多時候Servlet要和其他的資源進行互動，例如訪問數據庫，調用web service。在和這些資源互動的時候，Servlet不得不等待數據返回，然后才能夠繼續執行。這使得Servlet調用這些資源的時候阻塞。Servlet3.0通過引入異步處理解決了這個問題。異步處理允許線程調用資源的時候不被阻塞，而是直接返回。AsyncContext負責管理從資源來的回應。AsyncContext決定該回應是應該被原來的線程處理還是應該分發給容器中其他的資源。AsyncContext有一些方法如start，dispatch和complete來執行異步處理。 
要想使用Servlet3.0的異步處理，我們需要設置@Webservlet和@WebFilter注解的asyncSupport屬性。這個屬性是布爾值，缺省值是false。 
Servlet3.0的異步處理可以很好的和AJAX配合。在Servlet的init方法中，我們能夠訪問數據庫或從JMS讀取消息。在doGet或doPost方法中，我們能夠啟動異步處理，AsyncContext會通過AsyncEvent和AsyncListener來管理線程和數據庫操作/JMS操作自己的關系。