Nacos报错，failed to req API:/nacos/v1/ns/instance after all servers([localhost:8848]) tried: failed to

1.Nacos单机启动报错

java.lang.IllegalStateException: failed to req API:/nacos/v1/ns/instance after all servers([localhost:8848]) tried: failed to req API:localhost:8848/nacos/v1/ns/instance. code:500 msg: java.net.ConnectException: Connection refused: connectat com.alibaba.nacos.client.naming.net.NamingProxy.reqAPI(NamingProxy.java:464) ~[nacos-client-1.1.1.jar:na]at com.alibaba.nacos.client.naming.net.NamingProxy.reqAPI(NamingProxy.java:386) ~[nacos-client-1.1.1.jar:na]at com.alibaba.nacos.client.naming.net.NamingProxy.registerService(NamingProxy.java:188) ~[nacos-client-1.1.1.jar:na]at com.alibaba.nacos.client.naming.NacosNamingService.registerInstance(NacosNamingService.java:205) ~[nacos-client-1.1.1.jar:na]at com.alibaba.nacos.client.naming.NacosNamingService.registerInstance(NacosNamingService.java:184) ~[nacos-client-1.1.1.jar:na]at com.alibaba.cloud.nacos.registry.NacosServiceRegistry.register(NacosServiceRegistry.java:61) ~[spring-cloud-alibaba-nacos-discovery-2.1.0.RELEASE.jar:2.1.0.RELEASE]at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.register(AbstractAutoServiceRegistration.java:239) [spring-cloud-commons-2.2.1.RELEASE.jar:2.2.1.RELEASE]at com.alibaba.cloud.nacos.registry.NacosAutoServiceRegistration.register(NacosAutoServiceRegistration.java:74) [spring-cloud-alibaba-nacos-discovery-2.1.0.RELEASE.jar:2.1.0.RELEASE]at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.start(AbstractAutoServiceRegistration.java:138) [spring-cloud-commons-2.2.1.RELEASE.jar:2.2.1.RELEASE]at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.bind(AbstractAutoServiceRegistration.java:101) [spring-cloud-commons-2.2.1.RELEASE.jar:2.2.1.RELEASE]at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.onApplicationEvent(AbstractAutoServiceRegistration.java:88) [spring-cloud-commons-2.2.1.RELEASE.jar:2.2.1.RELEASE]at org.springframework.cloud.client.serviceregistry.AbstractAutoServiceRegistration.onApplicationEvent(AbstractAutoServiceRegistration.java:47) [spring-cloud-commons-2.2.1.RELEASE.jar:2.2.1.RELEASE]at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) [spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE]at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) [spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE]at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) [spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE]at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:403) [spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE]at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:360) [spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE]at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:165) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:553) [spring-context-5.2.2.RELEASE.jar:5.2.2.RELEASE]at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:141) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:747) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]at org.springframework.boot.SpringApplication.run(SpringApplication.java:315) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]at org.springframework.boot.SpringApplication.run(SpringApplication.java:1226) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]at org.springframework.boot.SpringApplication.run(SpringApplication.java:1215) [spring-boot-2.2.2.RELEASE.jar:2.2.2.RELEASE]at com.apple.springcloud.PaymentMain9003.main(PaymentMain9003.java:12) [classes/:na]

2.前提配置

1. 引入依赖

 com.alibaba.cloud spring-cloud-starter-alibaba-nacos-discovery org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-actuator

1. application.yml

server: port: 9003spring: application:   name: nacos-payment-provider cloud:   nacos:     discovery:       server-addr: localhost:8848#配置Nacos地址management: endpoints:   web:     exposure:       include: '*'

1. 主启动类加上@EnableDiscoveryClient注解

3.我的解决

1. 开启Nacos服务
2. 再次检查yml文件配置，注意缩进
3. 我查询了很多网上的文章，最后都没有解决，后来我决定先访问 http://localhost:8848/nacos/#/login 试一下，发现Nacos报错，是跟数据库相关的，“No DataSource set”，然后我想起来之前配置了Nacos持久化，所以访问的是mysql，于是——>开启mysql服务——>重启Nacos——>大功告成