一，報錯內(nèi)容

當(dāng)使用gateway的時候，我們可能會在gateway項(xiàng)目中引入一些額外的包，比如webmvc，starter-web等，當(dāng)然默認(rèn)是不需要這些的，而且這些放到里面也是會報錯的，一般使用的場景，比如你項(xiàng)目中引入elk，然后加入traceId的時候，就需要使用攔截器等，就會有問題，不過攔截器一般使用gateway的filter就可以了，這個組件會在后面做講解，引用了會有依賴沖突的，會報如下的錯誤

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.

Caused by: org.springframework.context.ApplicationContextException: Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean.

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:163)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:577)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:740)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:415)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:303)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1312)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1301)
	at com.hanvon.gateway.GatewayApplication.main(GatewayApplication.java:18)
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:210)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:180)
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:160)
	... 8 common frames omitted

二，解決方案

找到引用的包里面哪一些是有引用了spring-webmvc 或者 spring-boot-starter-web這個pom文件的，然后將這個進(jìn)行排除，解決jar沖突的依賴

三，原理

因?yàn)間ateway在其內(nèi)部導(dǎo)入了webflux包，但是webmvc和webflux是不能同時出現(xiàn)的，是有沖突的，所以一般做法就是先忽略webmv 包，但是如果必須要使用的話，我們可以進(jìn)行合理的拆分，將一些功能拆分出來，使用gateway里面中一些GatewayFilterFactory，GatewayPredicate來處理我們需要處理的邏輯