Spring Boot java.lang.NoClassDefFoundError: io/undertow/servlet/api/DeploymentManager

异常描述

启动SpringBoot项目控制台报了关于undertow NoClassDefFoundError 的异常，详细报错信息如下所示：

org.springframework.context.ApplicationContextException: Unable to start embedded container;
nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'undertowEmbeddedServletContainerFactory' 
defined in class path resource [org/springframework/boot/autoconfigure/web/EmbeddedServletContainerAutoConfiguration$EmbeddedUndertow.class]:
Post-processing of merged bean definition failed; nested exception is java.lang.NoClassDefFoundError: io/undertow/servlet/api/DeploymentManager

重点最后一句：java.lang.NoClassDefFoundError: io/undertow/servlet/api/DeploymentManager

解决方法

添加`undertow-servlet的依赖pom即可解决，pom文件内容如下：

        <dependency>
            <groupId>io.undertow</groupId>
            <artifactId>undertow-servlet</artifactId>
        </dependency>

然后查看导入的依赖发现已经拥有DeploymentManager这个接口，重新运行项目即可。