【spring boot】整合LCN，启动spring boot2.0.3 启动报错：Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean.

spring boot 2.0.3启动报错：

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-10-24 14:49:06.108 ERROR 14932 --- [           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:155) ~[spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:544) ~[spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at com.swapping.springcloud.ms.member.SpringcloudMsMemberApplication.main(SpringcloudMsMemberApplication.java:16) [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:204) ~[spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:178) ~[spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:152) ~[spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
    ... 8 common frames omitted

解决之路：

首先，在启动类上添加注解@EnableAutoConfiguration 或 @SpringBootApplication 这种 解决方案 ，都是无效的

其次，maven编译install这个spring boot服务，打包成功【如果这一步失败，需要查看一下失败原因，然后解决】

最后，仔细观察错误

Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean

猛然发现，本spring boot服务启动是以web服务启动，但是在jar依赖中找了半天没有找到tomcat的相关jar包，所以，我是缺少了这样一个jar包：

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

因为这个spring boot是一个子模块module，依赖于父层pom.xml的spring boot2.0.3，所以jar依赖没有写<version>，如果需要你可以自己指定！

最后，服务成功启动！！