java.net.UnknownHostException: nacos-payment-provider] with root cause

使用的 cloud-alibaba 2021.0.1.0+ springboot2.6.8版本

问题描述

服务都注册到了注册中心，但是通过RestTemplate 使用服务名称来调用的时候却报了如下错误。

2022-09-05 10:49:26.111 ERROR 98844 --- [p-nio-83-exec-1] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.web.client.ResourceAccessException: I/O error on GET request for "http://nacos-payment-provider/payment/nacos/777": nacos-payment-provider; nested exception is java.net.UnknownHostException: nacos-payment-provider] with root cause

java.net.UnknownHostException: nacos-payment-provider
	at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:184) ~[na:1.8.0_101]
	at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) ~[na:1.8.0_101]
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_101]
	at java.net.Socket.connect(Socket.java:589) ~[na:1.8.0_101]
	at java.net.Socket.connect(Socket.java:538) ~[na:1.8.0_101]
	at sun.net.NetworkClient.doConnect(NetworkClient.java:180) ~[na:1.8.0_101]
	at sun.net.www.http.HttpClient.openServer(HttpClient.java:432) ~[na:1.8.0_101]
	at sun.net.www.http.HttpClient.openServer(HttpClient.java:527) ~[na:1.8.0_101]
	at sun.net.www.http.HttpClient.(HttpClient.java:211) ~[na:1.8.0_101]
	at sun.net.www.http.HttpClient.New(HttpClient.java:308) ~[na:1.8.0_101]
	at sun.net.www.http.HttpClient.New(HttpClient.java:326) ~[na:1.8.0_101]
	at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1169) ~[na:1.8.0_101]
	at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1105) ~[na:1.8.0_101]
	at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:999) ~[na:1.8.0_101]
	at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:933) ~[na:1.8.0_101]
	at org.springframework.http.client.SimpleBufferingClientHttpRequest.executeInternal(SimpleBufferingClientHttpRequest.java:76) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.http.client.AbstractBufferingClientHttpRequest.executeInternal(AbstractBufferingClientHttpRequest.java:48) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.http.client.AbstractClientHttpRequest.execute(AbstractClientHttpRequest.java:66) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.client.RestTemplate.doExecute(RestTemplate.java:776) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.client.RestTemplate.execute(RestTemplate.java:711) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.client.RestTemplate.getForObject(RestTemplate.java:334) ~[spring-web-5.3.20.jar:5.3.20]
	at com.gzl.cn.controller.OrderNacosController.paymentInfo(OrderNacosController.java:21) ~[classes/:na]
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_101]
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_101]
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_101]
	at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_101]
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:150) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:117) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:895) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:808) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1067) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:963) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:655) ~[tomcat-embed-core-9.0.63.jar:4.0.FR]
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883) ~[spring-webmvc-5.3.20.jar:5.3.20]
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:764) ~[tomcat-embed-core-9.0.63.jar:4.0.FR]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:227) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53) ~[tomcat-embed-websocket-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.20.jar:5.3.20]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.20.jar:5.3.20]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:96) ~[spring-boot-actuator-2.6.8.jar:2.6.8]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.20.jar:5.3.20]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201) ~[spring-web-5.3.20.jar:5.3.20]
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:117) ~[spring-web-5.3.20.jar:5.3.20]
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:189) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:162) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:197) ~[tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:541) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:135) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:360) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:399) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:890) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1743) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) [tomcat-embed-core-9.0.63.jar:9.0.63]
	at java.lang.Thread.run(Thread.java:745) [na:1.8.0_101]

RestTemplate代码如下：

@Configuration
public class ApplicationContextBean {
    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }
}

注册中心：显示的服务也注册上去了

解决过程

打开依赖会发现一个问题，低版本当中引入注册中心，他都会引入Ribbon。但是这次却没有发现Ribbon的踪影，好像是cloud比较高的版本就不使用netflix当中的Ribbon了。

最后终于找到了解决方法。在pom中添加依赖

<dependency>
    <groupId>org.springframework.cloudgroupId>
    <artifactId>spring-cloud-starter-loadbalancerartifactId>
dependency>

2018年12月cloud官网对外宣布： https://spring.io/blog/2018/12/12/spring-cloud-greenwich-rc1-available-now

如下组件都进行了替换：