一、问题描述：SpringCloud + GateWay + Eureka访问出现404，Not Found

现象：网关成功注册进Eureka，但是通过网关访问时出现404

Whitelabel Error Page
This application has no configured error view, so you are seeing this as a fallback.

Mon Jun 05 16:33:18 CST 2023
[cb64c1a3-3] There was an unexpected error (type=Not Found, status=404).
org.springframework.web.server.ResponseStatusException: 404 NOT_FOUND
	at org.springframework.web.reactive.resource.ResourceWebHandler.lambda$handle$1(ResourceWebHandler.java:408)
	Suppressed: The stacktrace has been enhanced by Reactor, refer to additional information below: 
Error has been observed at the following site(s):
	*__checkpoint ⇢ org.springframework.cloud.gateway.filter.WeightCalculatorWebFilter [DefaultWebFilterChain]
	*__checkpoint ⇢ HTTP GET "/payment/timeout/1" [ExceptionHandlingWebHandler]
Original Stack Trace:
		at org.springframework.web.reactive.resource.ResourceWebHandler.lambda$handle$1(ResourceWebHandler.java:408)
		at reactor.core.publisher.MonoDefer.subscribe(MonoDefer.java:44)
		at reactor.core.publisher.Mono.subscribe(Mono.java:4397)
		at reactor.core.publisher.FluxSwitchIfEmpty$SwitchIfEmptySubscriber.onComplete(FluxSwitchIfEmpty.java:82)
		at reactor.core.publisher.MonoFlatMap$FlatMapMain.onComplete(MonoFlatMap.java:181)
		at reactor.core.publisher.MonoNext$NextSubscriber.onComplete(MonoNext.java:102)
		at reactor.core.publisher.FluxConcatMap$ConcatMapImmediate.drain(FluxConcatMap.java:368)

二、解决方案:

可以通过以下几种方式尝试解决，不是必须都配置，根据自己项目情况处理。

1、 配置 filters: - StripPrefix=1

配置 filters: - StripPrefix=1，与路由id同级，去除前缀

2、删除冲突依赖

网关中如果有 spring-boot-starter-actuator、spring-boot-starter-web 依赖，删除。

3、检查启动类

启动类没有直接写在主包下面，而是写在了子包下面，需要在启动类加上@ComponentScan(“xxx”)，xxx一定是你的主包名。

4、检查配置文件

检查配置文件中gateway相关的层级还有空格情况。

application.yml参考：

server:
  port: 9527

spring:
  application:
    name: cloud-gateway #微服务应用的名字
  cloud:
    gateway:
      routes:
        - id: payment_routh #payment_route    #路由的ID，没有固定规则但要求唯一，建议配合服务名
          uri: http://localhost:8001      #匹配后提供服务的路由地址
          predicates:
            - Path=/payment/timeout/**        # 断言，路径相匹配的进行路由
          filters:
            - StripPrefix=1
        - id: payment_routh2 #payment_route    #路由的ID，没有固定规则但要求唯一，建议配合服务名
          uri: http://localhost:8001          #匹配后提供服务的路由地址
          predicates:
            - Path=/payment/ok/**         # 断言，路径相匹配的进行路由
          filters:
            - StripPrefix=1
eureka:
  client:
    register-with-eureka: true #向注册中心注册自己
    fetch-registry: true #从EurekaServer抓取已有的注册信息，集群必须设置成true，才能配合ribbon负载均衡
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka
  instance:
    instance-id: gateway9527 #主机名称修改
    prefer-ip-address: true #访问路径可以显示ip
    hostname: cloud-gateway-service

如果这几种办法都没有解决，也可以尝试将target删除，重新编译试试。