项目场景：

在练习SpringCloud时，Eureka客户端(client)出现报错：Cannot execute request on any known server

问题描述

正常启动SpringCloud的Server端和Client端，结果发现Server端的控制台有个Error提示，如下：

2023-02-14 22:57:03.931  WARN 27792 --- [nfoReplicator-0] c.n.discovery.InstanceInfoReplicator     : There was a problem with the instance info replicatorcom.netflix.discovery.shared.transport.TransportException: Cannot execute request on any known serverat com.netflix.discovery.shared.transport.decorator.RetryableEurekaHttpClient.execute(RetryableEurekaHttpClient.java:112) ~[eureka-client-1.9.25.jar:1.9.25]at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.register(EurekaHttpClientDecorator.java:56) ~[eureka-client-1.9.25.jar:1.9.25]at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$1.execute(EurekaHttpClientDecorator.java:59) ~[eureka-client-1.9.25.jar:1.9.25]at com.netflix.discovery.shared.transport.decorator.SessionedEurekaHttpClient.execute(SessionedEurekaHttpClient.java:77) ~[eureka-client-1.9.25.jar:1.9.25]at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.register(EurekaHttpClientDecorator.java:56) ~[eureka-client-1.9.25.jar:1.9.25]at com.netflix.discovery.DiscoveryClient.register(DiscoveryClient.java:873) ~[eureka-client-1.9.25.jar:1.9.25]at com.netflix.discovery.InstanceInfoReplicator.run(InstanceInfoReplicator.java:121) ~[eureka-client-1.9.25.jar:1.9.25]at com.netflix.discovery.InstanceInfoReplicator$1.run(InstanceInfoReplicator.java:101) [eureka-client-1.9.25.jar:1.9.25]at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_341]at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_341]at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_341]at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) [na:1.8.0_341]at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_341]at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_341]at java.lang.Thread.run(Thread.java:750) [na:1.8.0_341]

com.sun.jersey.api.client.ClientHandlerException: javax.net.ssl.SSLException: Unsupported or unrecognized SSL messageat com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:187) ~[jersey-apache-client4-1.19.1.jar:1.19.1]at com.sun.jersey.api.client.filter.GZIPContentEncodingFilter.handle(GZIPContentEncodingFilter.java:123) ~[jersey-client-1.19.1.jar:1.19.1]at com.netflix.discovery.EurekaIdentityHeaderFilter.handle(EurekaIdentityHeaderFilter.java:27) ~[eureka-client-1.9.25.jar:1.9.25]at com.sun.jersey.api.client.Client.handle(Client.java:652) ~[jersey-client-1.19.1.jar:1.19.1]at com.sun.jersey.api.client.WebResource.handle(WebResource.java:682) ~[jersey-client-1.19.1.jar:1.19.1]

原因分析：

看提示意思是没有找到要注册的服务端，即你的注册地址可能写错了。
回头发现，其服务的配置文件写的注册地址是：https://localhost:8761/eureka，
原来是我把http写成了https，改回来再次启动服务就没有上面报错了。
（在写代码时还是要多加仔细啊）