Spring Cloud Gateway 不适用于 DiscoveryClientRouteDefinitionLocator答案

【问题标题】：Spring Cloud Gateway doesn't work with DiscoveryClientRouteDefinitionLocatorSpring Cloud Gateway 不适用于 DiscoveryClientRouteDefinitionLocator
【发布时间】：2021-03-31 17:35:19
【问题描述】：

当我使用这样的路由统计时，我正在使用 Spring 云网关（它工作正常）：

@Bean
RouteLocator routeLocator(RouteLocatorBuilder builder) {
    return builder.routes()
            .route((r) -> r.path("/customers/**").uri("http://localhost:8081/"))
            .route((r) -> r.path("/products/**").uri("http://localhost:8082/"))
            .build();
}

但是当我想使用带有 DiscoveryClientRouteDefinitionLocator 的动态路由时，它不起作用这是我的功能：

@Bean
DiscoveryClientRouteDefinitionLocator definitionLocator(
        ReactiveDiscoveryClient rdc,
        DiscoveryLocatorProperties properties) {
    return new DiscoveryClientRouteDefinitionLocator(rdc, properties);
}

这是我的 application.properties ：

server.port=8888
spring.application.name=gateway-service
spring.cloud.discovery.enabled=true

当我调用这个 uri http://localhost:8888/PRODUCT-SERVICE/products 我得到：

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

Tue Dec 22 00:42:19 WEST 2020
[97127699-3] There was an unexpected error (type=Internal Server Error, status=500).

控制台产生的异常：

    java.net.UnknownHostException: failed to resolve 'DESKTOP-B8APKA3.mshome.net' after 4 queries 
    at io.netty.resolver.dns.DnsResolveContext.finishResolve(DnsResolveContext.java:1013) ~[netty-resolver-dns-4.1.55.Final.jar:4.1.55.Final]
    Suppressed: reactor.core.publisher.FluxOnAssembly$OnAssemblyException: 
Error has been observed at the following site(s):
    |_ checkpoint ⇢ org.springframework.cloud.gateway.filter.WeightCalculatorWebFilter [DefaultWebFilterChain]
    |_ checkpoint ⇢ org.springframework.boot.actuate.metrics.web.reactive.server.MetricsWebFilter [DefaultWebFilterChain]
    |_ checkpoint ⇢ HTTP GET "/CUSTOMER-SERVICE/customers" [ExceptionHandlingWebHandler]
    |_ checkpoint ⇢ org.springframework.cloud.gateway.filter.WeightCalculatorWebFilter [DefaultWebFilterChain]
    |_ checkpoint ⇢ org.springframework.boot.actuate.metrics.web.reactive.server.MetricsWebFilter [DefaultWebFilterChain]
    |_ checkpoint ⇢ HTTP GET "/PRODUCT-SERVICE/products" [ExceptionHandlingWebHandler]
Stack trace:
        at io.netty.resolver.dns.DnsResolveContext.finishResolve(DnsResolveContext.java:1013) ~[netty-resolver-dns-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.resolver.dns.DnsResolveContext.tryToFinishResolve(DnsResolveContext.java:966) ~[netty-resolver-dns-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.resolver.dns.DnsResolveContext.query(DnsResolveContext.java:414) ~[netty-resolver-dns-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.resolver.dns.DnsResolveContext.onResponse(DnsResolveContext.java:625) ~[netty-resolver-dns-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.resolver.dns.DnsResolveContext.access$400(DnsResolveContext.java:63) ~[netty-resolver-dns-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.resolver.dns.DnsResolveContext$2.operationComplete(DnsResolveContext.java:458) ~[netty-resolver-dns-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.util.concurrent.DefaultPromise.notifyListener0(DefaultPromise.java:578) [netty-common-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.util.concurrent.DefaultPromise.notifyListeners0(DefaultPromise.java:571) [netty-common-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.util.concurrent.DefaultPromise.notifyListenersNow(DefaultPromise.java:550) [netty-common-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.util.concurrent.DefaultPromise.notifyListeners(DefaultPromise.java:491) [netty-common-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.util.concurrent.DefaultPromise.setValue0(DefaultPromise.java:616) [netty-common-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.util.concurrent.DefaultPromise.setSuccess0(DefaultPromise.java:605) [netty-common-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.util.concurrent.DefaultPromise.trySuccess(DefaultPromise.java:104) [netty-common-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.resolver.dns.DnsQueryContext.trySuccess(DnsQueryContext.java:201) ~[netty-resolver-dns-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.resolver.dns.DnsQueryContext.finish(DnsQueryContext.java:193) ~[netty-resolver-dns-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.resolver.dns.DnsNameResolver$DnsResponseHandler.channelRead(DnsNameResolver.java:1230) ~[netty-resolver-dns-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) ~[netty-codec-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.nio.AbstractNioMessageChannel$NioMessageUnsafe.read(AbstractNioMessageChannel.java:93) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:719) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:655) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:581) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:493) ~[netty-transport-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989) ~[netty-common-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[netty-common-4.1.55.Final.jar:4.1.55.Final]
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[netty-common-4.1.55.Final.jar:4.1.55.Final]
        at java.lang.Thread.run(Unknown Source) ~[na:1.8.0_251]

【问题讨论】：

你解决了吗？
是的，我确实是 DNS 问题，所以我重置了网络参数并且它可以工作。
是的，对我来说重启电脑有帮助。

标签： java spring-cloud-gateway eclipse-jee

【解决方案1】：

这是一个 DNS 问题，所以我重置了网络参数并且它可以工作。如果您重置网络但仍然无法正常工作，则需要添加此属性：

eureka.instance.prefer-ip-address=true

在你的所有application.properties服务中注册主机的IP地址而不是容器的主机名到Eureka服务器。

【讨论】：

【解决方案2】：

我遇到了同样的问题。我创建了这个 bean，它解决了我的问题。

@Bean
public HttpClient httpClient() {
    return HttpClient.create().resolver(DefaultAddressResolverGroup.INSTANCE);
}

【讨论】：

【解决方案3】：

将spring.cloud.discovery.enabled=true 添加到application.properties。

【讨论】：

【解决方案4】：

如果配置没有问题，重启电脑试试。

【讨论】：