SpringCloud微服务练手分步骤学习Nacos服务注册与配置中心本文按编程操作步骤来写先引入依赖再写配置再给启动类加注解。跟着步骤敲就能把 Nacos 的服务注册与配置中心跑通。第0步 环境准备JDK 8 / Maven 3.6 / IDEASpring Boot 2.7.15Spring Cloud 2021.0.5Spring Cloud Alibaba 2021.0.1.0Nacos 服务端 2.2.x单机部署在 192.168.150.101:8848项目结构父工程统一管理版本feign-demo-parent # 父工程pom ├── nacos-common # 公共模块实体 Feign接口 ├── feign-provider # 服务提供者注册Nacos 配置中心 └── feign-consumer # 服务消费者Feign远程调用第一步 父工程引入依赖统一管理版本父工程是 pom 工程用 dependencyManagement 锁定版本子模块不用再写版本号。dependencyManagementdependenciesdependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-dependencies/artifactIdversion2.7.15/versiontypepom/typescopeimport/scope/dependencydependencygroupIdcom.alibaba.cloud/groupIdartifactIdspring-cloud-alibaba-dependencies/artifactIdversion2021.0.1.0/versiontypepom/typescopeimport/scope/dependencydependencygroupIdorg.springframework.cloud/groupIdartifactIdspring-cloud-dependencies/artifactIdversion2021.0.5/versiontypepom/typescopeimport/scope/dependency/dependencies/dependencyManagement说明三个 BOM 一个都不能少尤其 spring-cloud-dependencies否则 openfeign、loadbalancer 版本会解析成 unknown 报错。第二步 公共模块 nacos-common实体 Feign接口公共模块放实体类和 Feign 接口provider 和 consumer 都引用它。实体类 UserDatapublicclassUser{privateLongid;privateStringname;privateStringmsg;}Feign 接口 UserFeignApiname 必须和 provider 的 application.name 完全一致FeignClient(namenacos-provider)publicinterfaceUserFeignApi{GetMapping(/user/{id})UsergetUser(PathVariable(id)Longid);}第三步 服务提供者 feign-provider作用把自己注册到 Nacos服务注册发现并从 Nacos 配置中心读配置。3.1 引入依赖dependenciesdependencygroupIdorg.springframework.boot/groupIdartifactIdspring-boot-starter-web/artifactId/dependencydependencygroupIdcom.alibaba.cloud/groupIdartifactIdspring-cloud-starter-alibaba-nacos-discovery/artifactId/dependencydependencygroupIdcom.alibaba.cloud/groupIdartifactIdspring-cloud-starter-alibaba-nacos-config/artifactId/dependencydependencygroupIdorg.springframework.cloud/groupIdartifactIdspring-cloud-starter-bootstrap/artifactId/dependencydependencygroupIdcom.demo/groupIdartifactIdnacos-common/artifactIdversion0.0.1/version/dependency/dependencies3.2 写配置文件bootstrap.yml服务名 Nacos 地址 配置中心 shared-configsspring:application:name:nacos-providercloud:nacos:discovery:server-addr:192.168.150.101:8848config:server-addr:192.168.150.101:8848file-extension:yamlshared-configs:-data-id:nacos-provider.yamlgroup:DEFAULT_GROUPrefresh:trueapplication.yml本地端口server:port:80813.3 启动类加注解SpringBootApplicationEnableDiscoveryClient// 开启服务注册发现publicclassProviderApplication{publicstaticvoidmain(String[]args){SpringApplication.run(ProviderApplication.class,args);}}3.4 写 Controller读配置 支持热更新RestControllerRefreshScope// 支持 Nacos 配置热更新publicclassUserController{Value(${demo.msg:默认消息})privateStringmsg;GetMapping(/user/{id})publicUsergetUser(PathVariableLongid){UserusernewUser();user.setId(id);user.setName(provider返回用户);user.setMsg(msg);returnuser;}}第四步 服务消费者 feign-consumer作用通过 Feign 远程调用 provider实现服务间通信。4.1 引入依赖openfeign loadbalancer nacos-discovery commondependencygroupIdorg.springframework.cloud/groupIdartifactIdspring-cloud-starter-openfeign/artifactId/dependencydependencygroupIdorg.springframework.cloud/groupIdartifactIdspring-cloud-starter-loadbalancer/artifactId/dependencydependencygroupIdcom.alibaba.cloud/groupIdartifactIdspring-cloud-starter-alibaba-nacos-discovery/artifactId/dependencydependencygroupIdcom.demo/groupIdartifactIdnacos-common/artifactIdversion0.0.1/version/dependency4.2 启动类加注解SpringBootApplicationEnableDiscoveryClientEnableFeignClients(basePackages{com.demo.common.feign,com.demo.feignconsumer.feign})publicclassConsumerApplication{publicstaticvoidmain(String[]args){SpringApplication.run(ConsumerApplication.class,args);}}4.3 写 Controller注入 Feign 接口RestControllerpublicclassConsumerController{ResourceprivateUserFeignApiuserFeignApi;GetMapping(/getUser/{id})publicUsergetUser(PathVariableLongid){returnuserFeignApi.getUser(id);// Feign 远程调用 provider}}第五步 测试验证先启动 Nacos 服务端192.168.150.101:8848单机模式启动 feign-provider到 Nacos 控制台【服务管理-服务列表】确认 nacos-provider 已注册启动 feign-consumer浏览器访问 http://localhost:8082/getUser/1返回 provider 的数据msg 取自配置中心说明服务注册 配置中心都打通修改 Nacos 后台 demo.msg 并发布不重启服务msg 自动变化验证热更新第六步 踩坑记录坑1loadbalancer / openfeign 报 unknown - 父pom缺 spring-cloud-dependencies BOM坑2serviceName is blank - SpringBoot2.4 没加 spring-cloud-starter-bootstrapbootstrap.yml 没加载坑3注入 UserFeignApi 找不到 Bean - EnableFeignClients 没扫到公共模块的 feign 包要指定 basePackages坑4配置中心读不到值 - shared-configs 需 bootstrap 或 spring.config.import 激活总结按引入依赖 - 写配置 - 启动类加注解 - 写接口的步骤就能把 Nacos 的两大能力服务注册发现 配置中心跑通。版本匹配和 SpringBoot2.4 的 bootstrap 机制变化是最容易踩坑的地方。
