在搭建gateway服务的时候，启动出现以下问题：

Description:

An attempt was made to call a method that does not exist. The attempt was made from the following location:

    org.springframework.cloud.gateway.config.GatewayAutoConfiguration$NettyConfiguration.buildConnectionProvider(GatewayAutoConfiguration.java:798)

The following method did not exist:

    reactor.netty.resources.ConnectionProvider$Builder.evictInBackground(Ljava/time/Duration;)Lreactor/netty/resources/ConnectionProvider$ConnectionPoolSpec;

The method's class, reactor.netty.resources.ConnectionProvider$Builder, is available from the following locations:

    jar:file:/D:/apache-maven-3.3.9/repository/io/projectreactor/netty/reactor-netty/0.9.12.RELEASE/reactor-netty-0.9.12.RELEASE.jar!/reactor/netty/resources/ConnectionProvider$Builder.class

The class hierarchy was loaded from the following locations:

    reactor.netty.resources.ConnectionProvider.Builder: file:/D:/apache-maven-3.3.9/repository/io/projectreactor/netty/reactor-netty/0.9.12.RELEASE/reactor-netty-0.9.12.RELEASE.jar
    reactor.netty.resources.ConnectionProvider.ConnectionPoolSpec: file:/D:/apache-maven-3.3.9/repository/io/projectreactor/netty/reactor-netty/0.9.12.RELEASE/reactor-netty-0.9.12.RELEASE.jar

Action:

Correct the classpath of your application so that it contains a single, compatible version of reactor.netty.resources.ConnectionProvider$Builder

 这个看就是依赖导致的，应该是springBoot的和spring cloud版本不符导致的。我现在错误的版本是：Spring-boot是2.3.0.RELEASE，Spring-cloud是Hoxton.SR12这是不符合的。

改成：Spring-boot是2.3.0.RELEASE，Spring-cloud是Hoxton.SR8 或者 Spring-boot是2.3.12.RELEASE，Spring-cloud是Hoxton.SR12就可以了