Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean

版权声明：本文为博主原创文章，转载请声明。 https://blog.csdn.net/will_lam/article/details/83110462

spring-boot-starter-web版本从1.3.5.RELEASE升级2.0.4.RELEASE后，启动时报错：

org.springframework.context.ApplicationContextException: 
Unable to start web server; 
nested exception is org.springframework.context.ApplicationContextException: 
Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean.

排查后发现是引入的tomcat-embed-jasper版本太低，覆盖了spring-boot-starter-web下的tomcat-embed-core、tomcat-embed-el，导致spring-boot-starter-web的tomcat-embed-websocket跟tomcat-embed-core、tomcat-embed-el版本不匹配，
所以把tomcat-embed-jasper升级到跟spring-boot-starter-web对应的版本即可。

网上搜了一堆没什么卵用，特此记录下！

<dependency>
    <groupId>org.apache.tomcat.embed</groupId>
    <artifactId>tomcat-embed-jasper</artifactId>
    <version>8.0.33</version> //- 升级版本
</dependency>