tomcat启动失败Failed to start component ：A child container failed during start解决

org.apache.catalina.core.ContainerBase   : A child container failed during start

Caused by: java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component 

Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[/backgroundweb]]

2018-10-18 17:55:57.540 ERROR 16344 --- [cat-startStop-1] org.apache.catalina.core.ContainerBase   : A child container failed during start

java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[/backgroundweb]]
	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$StartChild.call(ContainerBase.java:1420)
	at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1410)
	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[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[/backgroundweb]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
	... 6 common frames omitted
Caused by: org.apache.catalina.LifecycleException: Failed to start component [Pipeline[StandardEngine[Tomcat].StandardHost[localhost].TomcatEmbeddedContext[/backgroundweb]]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5166)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	... 6 common frames omitted
Caused by: org.apache.catalina.LifecycleException: Failed to start component [org.apache.catalina.authenticator.NonLoginAuthenticator[/backgroundweb]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
	at org.apache.catalina.core.StandardPipeline.startInternal(StandardPipeline.java:182)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	... 8 common frames omitted
Caused by: java.lang.NoSuchMethodError: javax.servlet.ServletContext.getVirtualServerName()Ljava/lang/String;
	at org.apache.catalina.authenticator.AuthenticatorBase.startInternal(AuthenticatorBase.java:1181)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	... 10 common frames omitted

原因就是引入的第三方库依赖了 servlet-api， 在Dependencies中打开依赖的树形结构，找到servlet-api包， 看看是你引入的哪个库引入了servlet-api，然后排除这个包即可。我这里是spring-data-hadoop-hbase引入了servlet-api包，排除方法如下：

        <dependency>
            <groupId>org.springframework.data</groupId>
            <artifactId>spring-data-hadoop-hbase</artifactId>
            <version>2.4.0.RELEASE</version>
            <exclusions>
                <exclusion>
                    <groupId>log4j</groupId>
                    <artifactId>log4j</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>org.slf4j</groupId>
                    <artifactId>slf4j-log4j12</artifactId>
                </exclusion>
                <exclusion>
                    <groupId>javax.servlet</groupId>
                    <artifactId>servlet-api</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

即可启动成功。