Dubbo: spring boot with dubbo 2.6.3, cause ‘ Cannot initialize context because there is already a root application context present - check whether you have multiple ContextLoader* definitions in your web.xml’

[iorilchen]

Environment

• Dubbo version: 2.6.3
• Operating System version: Linux ubuntu 4.9.0
• Java version: 1.8
• tomcat-7.0.82.4
• spring boot 2.0.1.RELEASE
  

  Steps to reproduce this issue

a web spring boot project use dubbo as a consumer,when deploy it to tomcat-7.0.82.4 ,start the applicaton failed, but it start success in IDE without tomcat

Pls. provide [GitHub address] to reproduce this issue.

Expected Result

web project start success

Actual Result

failed

If there is an exception, please attach the exception trace:

[ERROR] - Exception sending context initialized event to listener instance of class org.springframework.web.context.ContextLoaderListener
java.lang.IllegalStateException: Cannot initialize context because there is already a root application context present - check whether you have multiple ContextLoader* definitions in your web.xml!
        at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:262)
        at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:103)
        at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:5110)
        at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5633)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:1015)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:991)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:652)
        at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1296)
        at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:2038)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        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)

[chenlushun]

这个问题跟DUBBO没关系吧？
你检查一下，web.xml 里面是不是配置了ContextLoaderListener？Spring boot是不需要配置ContextLoaderListener的

[iorilchen]

我这个工程spring boot里没有web.xml。 在intellij里启动main可以，发布到tomcat 里启动就报这个。回退到之前一直用的2.6.2就好了。还没来得及进一步分析原因

[zxbu]

有同样问题，回退到2.6.2就好了，未有任何改动。

[SawamuraEriri]

回退到2.6.2可以 , 2.6.3 tomcat9启动报内存溢出

[kexianjun]

May be the same problem as #2538

[iorilchen]

ApplicationContextHolder implements ApplicationContextAware
怀疑是
applicationContext.xml里配置了

引起。 在filter里要拿bean，如果是dubbo provider端可以用ServiceBean.getSpringContext().getBean(),
但如果是web客户端，ServiceBean.getSpringContext()为空，为了拿到applicationContext.xml配置的bean，就要用到applicationContextHolder

[beiwei30]

It's been addressed by ee21cea88855fea698e173d33421fd6c3adcc02f on 2.6.x and 393ffce5df5ac94a209914623d9a10bf94ef3b13 on 2.7

[zhangsongyang]

有同样问题，回退到2.6.2就好了，未有任何改动。但是为什么2.6.5就不行

[saillen]

dubbo 2.6.3 默认添加了 web-fragment.xml，这个特性基于 servlet 3.0 ，容器会自动扫描这个文件，dubbo-fragment.xml 里面添加一个ContextLoaderListener。Spring Boot 2.0 也基于 Servlet 3.0 添加这个listener，这样就会报错，算是Dubbo的bug。添加一个web.xml 关闭这个特性就好了。