照着教程弄的第一个 DEMO，结果启不来。
解决办法：在Controller 上面加上 @EnableAutoConfiguration
成功启动
Demo的其它内容及配置如下图，新建一个 空的 Maven 项目
Pom.xml
主界面：
Control.java
运行报错
:: Spring Boot :: (v2.2.5.RELEASE) 2020-03-06 08:41:45.942 INFO 8240 --- [ main] com.iron.HelloWorldMainApp : Starting HelloWorldMainApp on ChenJun with PID 8240 (F:\Project\SpringBoot\sprintboot01helloworld\target\classes started by Jimmy in F:\Project\SpringBoot\sprintboot01helloworld) 2020-03-06 08:41:45.947 INFO 8240 --- [ main] com.iron.HelloWorldMainApp : No active profile set, falling back to default profiles: default 2020-03-06 08:41:46.152 WARN 8240 --- [ main] ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: 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. 2020-03-06 08:41:46.302 ERROR 8240 --- [ main] o.s.boot.SpringApplication : Application run failed 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-2.2.5.RELEASE.jar:2.2.5.RELEASE] at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:544) ~[spring-context-5.2.4.RELEASE.jar:5.2.4.RELEASE] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE] at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE] at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) [spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE] at com.iron.HelloWorldMainApp.main(HelloWorldMainApp.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-2.2.5.RELEASE.jar:2.2.5.RELEASE] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:179) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE] at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:153) ~[spring-boot-2.2.5.RELEASE.jar:2.2.5.RELEASE] ... 8 common frames omitted Process finished with exit code 1
