啟動報錯：

Caused by: org.springframework.boot.context.embedded.EmbeddedServletContainerException: Unable to start embedded Tomcat
        at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.initialize(TomcatEmbeddedServletContainer.java:116)
        at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.<init>(TomcatEmbeddedServletContainer.java:83)
        at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getTomcatEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:530)
        at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:176)
        at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.createEmbeddedServletContainer(EmbeddedWebApplicationContext.java:164)
        at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:134)
        ... 13 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardServer[-1]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:158)
        at org.apache.catalina.startup.Tomcat.start(Tomcat.java:356)
        at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.initialize(TomcatEmbeddedServletContainer.java:97)
        ... 18 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Tomcat]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:158)
        at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:791)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:152)
        ... 20 more
Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Tomcat]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:158)
        at org.apache.catalina.core.StandardService.startInternal(StandardService.java:422)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:152)
        ... 22 more
Caused by: org.apache.catalina.LifecycleException: A child container failed during start
        at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:919)
        at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262)
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:152)
        ... 24 more
 

因為在hadoop-client中引入了servlet包 引發了衝突 去除即可解決問題

<dependency>
        <groupId>org.apache.hadoop</groupId>
        <artifactId>hadoop-client</artifactId>
        <version>2.9.0</version>
        <exclusions>
            <exclusion>
                <artifactId>jsp-api</artifactId>
                <groupId>javax.servlet.jsp</groupId>
            </exclusion>
            <exclusion>
                <artifactId>servlet-api</artifactId>
                <groupId>javax.servlet</groupId>
            </exclusion>
        </exclusions>
</dependency>