引言
SpringCloud与Nacos是目前非常热门的微服务开发框架和注册中心，然而在实际使用过程中，可能会遇到一些启动报错的问题。本文将介绍一些常见的启动报错及其解决方案，帮助读者快速排查和解决问题。
报错一：Failed to register value 'spring.cloud.nacos.discovery.server-addr'
报错信息
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'nacosDiscoveryClient' defined in class path resource [org/springframework/cloud/alibaba/nacos/discovery/NacosDiscoveryClientAutoConfiguration.class]: Unsatisfied dependency expressed through method 'nacosDiscoveryClient' parameter 0; nested exception is org.springframework.boot.autoconfigure.condition.ConditionEvaluationException: Failed to evaluate 'at org.springframework.boot.autoconfigure.condition.BeanTypeRegistry$OptimizedBeanTypeRegistry.get(BeanTypeRegistry.java:101)'
...
Caused by: org.springframework.boot.autoconfigure.condition.ConditionEvaluationException: Failed to evaluate 'org.springframework.boot.autoconfigure.condition.OnPropertyCondition'
...
Caused by: java.lang.IllegalStateException: Failed to register value 'spring.cloud.nacos.discovery.server-addr' as Spring Cloud Nacos Discovery configuration property: Property origin returned an invalid value from a binder: 'null'
解决方案
该报错的原因是配置文件中未正确配置Nacos的服务地址。我们需要在application.properties或application.yml文件中添加如下配置：
spring.cloud.nacos.discovery.server-addr=your-nacos-server-address
其中，your-nacos-server-address要替换为实际的Nacos服务地址。如果是使用默认端口号，一般为localhost:8848。
报错二：Connection refused: connect
报错信息
java.net.ConnectException: Connection refused: connect
...
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.cloud.alibaba.nacos.registry.NacosServiceRegistry' defined in class path resource [org/springframework/cloud/alibaba/nacos/registry/NacosServiceRegistryAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.alibaba.nacos.registry.NacosServiceRegistry]: Factory method 'nacosServiceRegistry' threw exception; nested exception is com.alibaba.nacos.api.exception.NacosException: com.alibaba.nacos.api.exception.NacosException: failed to req API:/nacos/v1/ns/instance after all servers([localhost:8848]) tried:
解决方案
该报错的原因是Nacos服务未成功启动。可能是Nacos服务未正常运行或端口号配置错误。我们需要确保Nacos服务已正确启动，并且检查Nacos服务的端口是否与配置文件中的端口一致。
报错三：Failed to auto configure a NacosServiceRegistry
报错信息
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.cloud.alibaba.nacos.registry.NacosServiceRegistry' defined in class path resource [org/springframework/cloud/alibaba/nacos/registry/NacosServiceRegistryAutoConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.cloud.alibaba.nacos.registry.NacosServiceRegistry]: Factory method 'nacosServiceRegistry' threw exception; nested exception is java.lang.IllegalArgumentException: Cannot parse address as either IP or FQDN. Neither IPv4 nor IPv6 nor FQDN
解决方案
该报错的原因是Nacos服务地址配置错误。我们需要在application.properties或application.yml文件中正确配置Nacos服务地址，并确保配置的地址为可用的IP地址或全限定域名。例如：
spring.cloud.nacos.discovery.server-addr=192.168.0.123:8848
结语
本文介绍了三种常见的SpringCloud启动Nacos报错及其解决方案。希望读者在使用SpringCloud与Nacos进行微服务开发时能够顺利启动和使用。如有其他报错或问题，请及时查阅官方文档或搜索相关解决方案。
本文来自极简博客，作者：雨后彩虹，转载请注明原文链接：SpringCloud启动Nacos报错解决方案
