解决springboot启动失败问题：Unable to start embedded container;

全部报错内容如下：

org.springframework.context.ApplicationContextException: Unable to start embedded container; nested exception is java.lang.IllegalStateException: Expected method not found: java.lang.NoSuchMethodException: org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedContext.addApplicationListener(org.apache.catalina.deploy.ApplicationListener)
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:137) ~[spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:535) ~[spring-context-4.3.3.RELEASE.jar:4.3.3.RELEASE]
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:761) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:371) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1186) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1175) [spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at com.springboot5.App.main(App.java:12) [classes/:na]
Caused by: java.lang.IllegalStateException: Expected method not found: java.lang.NoSuchMethodException: org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedContext.addApplicationListener(org.apache.catalina.deploy.ApplicationListener)
	at org.springframework.util.ClassUtils.getMethod(ClassUtils.java:628) ~[spring-core-4.3.3.RELEASE.jar:4.3.3.RELEASE]
	at org.springframework.boot.autoconfigure.websocket.TomcatWebSocketContainerCustomizer.addListener(TomcatWebSocketContainerCustomizer.java:86) ~[spring-boot-autoconfigure-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.autoconfigure.websocket.TomcatWebSocketContainerCustomizer.access$100(TomcatWebSocketContainerCustomizer.java:37) ~[spring-boot-autoconfigure-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.autoconfigure.websocket.TomcatWebSocketContainerCustomizer$1.customize(TomcatWebSocketContainerCustomizer.java:51) ~[spring-boot-autoconfigure-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.configureContext(TomcatEmbeddedServletContainerFactory.java:479) ~[spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.prepareContext(TomcatEmbeddedServletContainerFactory.java:221) ~[spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainerFactory.getEmbeddedServletContainer(TomcatEmbeddedServletContainerFactory.java:176) ~[spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.createEmbeddedServletContainer(EmbeddedWebApplicationContext.java:164) ~[spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.onRefresh(EmbeddedWebApplicationContext.java:134) ~[spring-boot-1.4.1.RELEASE.jar:1.4.1.RELEASE]
	... 8 common frames omitted

问题分析：我这个报错原因，网上查了半天，感觉应该是和jar包冲突有关，但找了半天也没找着冲突的jar包是哪个，但是jar包肯定跟tomcat有关，后来有个帖子说IDE集成tomcat会有影响，这个报错之前，我刚把Eclipse配置了RuntimeEnvironments,所以我再次把他去掉，问题解决。

解决步骤：Eclipse-Windows-perferences-RuntimeEnvironments-将tomcat去掉。