项目报错信息：

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.
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:156) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:544) ~[spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
	at com.atguigu.yygh.gateway.ServerGatewayApplication.main(ServerGatewayApplication.java:11) ~[classes/:na]
Caused by: org.springframework.context.ApplicationContextException: Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean.
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.getWebServerFactory(ServletWebServerApplicationContext.java:203) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:179) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:153) ~[spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]
	... 8 common frames omitted


Process finished with exit code 1

解决方法：

1，检查入口 Application 文件是否加了 @SpringBootApplication 注解，或者 @SpringBootConfiguration、@EnableAutoConfiguration 两个注解。

 

2，检查 pom.xml 是否正确添加 web 依赖：

3、在启动类中，.class的名称要与启动类名称相同（低级错误，本人就是这个错误。在编码时候使用了idea的自动补全功能，导致这个低级错误的出现！）

错误实例：

正确实例:

这真是一个很低级的错误，从这个错误中，可以反思进一步论证出： 编程是一项技术活儿和精细活儿，不论自身技术到了什么程度，都应该注意最基本的细节，否则会白白耗费自己大量的时间。

特此记录。