Caused by: java.lang.ClassCastException: org.springframework.web.SpringServletContainerInitializer cannot be cast to javax.servlet.ServletContainerInitializer。。。。。检查一下servlet-api是否冲突了？

原因：jar包发生冲突。在我的pom.xml文件中

<dependency>  
    <groupId>javax.servlet</groupId>      <gro