SpringBoot啟動時的異常信息如下：
1 "C:\Program Files\Java\jdk1.8.0_161\bin\java" ......... com.fangxing.javalearning.annotationlearning.ComponentScanApp 2 hello world 3
4 . ____ _ __ _ _ 5 /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
6 ( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
7 \\/ ___)| |_)| | | | | || (_| | ) ) ) ) 8 ' |____| .__|_| |_|_| |_\__, | / / / /
9 =========|_|==============|___/=/_/_/_/
10 :: Spring Boot :: (v2.0.0.RELEASE) 11
12 2018-04-03 22:25:07.232 INFO 4976 --- [ main] c.f.j.a.ComponentScanApp : Starting ComponentScanApp on DESKTOP-BHGM3HS with PID 4976 (started by hasee in D:\test\projects\java-learning) 13 2018-04-03 22:25:07.237 INFO 4976 --- [ main] c.f.j.a.ComponentScanApp : No active profile set, falling back to default profiles: default
14 2018-04-03 22:25:07.321 INFO 4976 --- [ main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@45f45fa1: startup date [Tue Apr 03 22:25:07 CST 2018]; root of context hierarchy 15 2018-04-03 22:25:07.664 WARN 4976 --- [ 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. 16 2018-04-03 22:25:08.238 ERROR 4976 --- [ main] o.s.boot.SpringApplication : Application run failed 17
18 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. 19 at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:155) ~[spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] 20 at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE] 21 at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] 22 at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:752) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] 23 at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:388) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] 24 at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] 25 at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] 26 at org.springframework.boot.SpringApplication.run(SpringApplication.java:1234) [spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] 27 at com.fangxing.javalearning.annotationlearning.ComponentScanApp.main(ComponentScanApp.java:15) [classes/:na] 28 Caused by: org.springframework.context.ApplicationContextException: Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean. 29 at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.getWebServerFactory(ServletWebServerApplicationContext.java:204) ~[spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] 30 at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:178) ~[spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] 31 at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:152) ~[spring-boot-2.0.0.RELEASE.jar:2.0.0.RELEASE] 32 ... 8 common frames omitted 33
34
35 Process finished with exit code 1
Spring Boot啟動出現錯誤，錯誤內容大概的意思是：未能加載嵌入的供web應用加載的空間，是因為缺少ServletWebServerFactory bean，在stackflow上面看到了這個錯誤的解決辦法，原文如下：
The scheduling guide isn't a web app so you probably have some mouldy stuff in your pom.xml from the REST guide? If you follow the instructions closely it should work. Another potential issue with the code you posted above is that your @EnableAutoConfiguration class is not used in the context, only as a main method (which may not be a problem for the scheduling guide but it probably is for a bunch of others).
這里，添加了一個@EnableAutoConfiguration注解來解決問題。
參考文檔：
https://blog.csdn.net/u010429286/article/details/52636753
http://stackoverflow.com/questions/21783391/spring-boot-unable-to-start-embeddedwebapplicationcontext-due-to-missing-embedd