1.pom添加nacos-discovery依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.demo</groupId>
        <artifactId>fast-cloud-2021.x-2.6.13</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>fast-gateway</artifactId>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <!--gateway是由springcloud开发的，所以要引入springcloud依赖；网关是由webflux+netty+reactor开发的，所以不需要tomcat，不需要starter-web-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
        </dependency>

        <--!如果接口报503，请检查pom中是否有spring-cloud-loadbalancer坐标-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-loadbalancer</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
    </dependencies>
</project>

2.修改application.yml

server:
  port: 8080
spring:
  application:
    name: fast-gateway
  cloud:
    gateway:
      routes:
          #如果接口报503，请检查pom中是否有spring-cloud-loadbalancer坐标
        - id: fast-auth
          # 网关转发地址，要和注册到nacos上的服务名一致,fast-auth服务也要注册到nacos上，加上下面nacos的配置就行。
          uri: lb://fast-auth
          predicates:
            - Path=/fast-auth/**
#          filters:
#            - StripPrefix=1
    nacos:
      server-addr: 127.0.0.1:8848
      discovery:
        username: nacos
        password: nacos

3.验证是否成功

访问fast-auth服务的test接口:localhost:8081/test,fast-auth的server.servlet.context-path: /fast-auth,通过网关访问：localhost:8080/fast-auth/test,能访问通即可，如果接口报503，请检查pom中是否有spring-cloud-loadbalancer坐标。