运行dubbo-samples-zookeeper，提示No such extension org.apache.dubbo.rpc.Protocol by name dubbo

[abcgis]

Exception in thread "main" java.lang.IllegalStateException: No such extension org.apache.dubbo.rpc.Protocol by name dubbo at org.apache.dubbo.common.extension.ExtensionLoader.findException(ExtensionLoader.java:618) at org.apache.dubbo.common.extension.ExtensionLoader.createExtension(ExtensionLoader.java:625) at org.apache.dubbo.common.extension.ExtensionLoader.getExtension(ExtensionLoader.java:424) at org.apache.dubbo.config.ServiceConfig.findConfigedPorts(ServiceConfig.java:644) at org.apache.dubbo.config.ServiceConfig.doExportUrlsFor1Protocol(ServiceConfig.java:444) at org.apache.dubbo.config.ServiceConfig.doExportUrls(ServiceConfig.java:325) at org.apache.dubbo.config.ServiceConfig.doExport(ServiceConfig.java:300) at org.apache.dubbo.config.ServiceConfig.export(ServiceConfig.java:206) at org.apache.dubbo.config.bootstrap.DubboBootstrap.lambda$exportServices$16(DubboBootstrap.java:943) at java.util.HashMap$Values.forEach(HashMap.java:981) at org.apache.dubbo.config.bootstrap.DubboBootstrap.exportServices(DubboBootstrap.java:930) at org.apache.dubbo.config.bootstrap.DubboBootstrap.start(DubboBootstrap.java:749) at org.apache.dubbo.config.spring.context.DubboBootstrapApplicationListener.onContextRefreshedEvent(DubboBootstrapApplicationListener.java:59) at org.apache.dubbo.config.spring.context.DubboBootstrapApplicationListener.onApplicationContextEvent(DubboBootstrapApplicationListener.java:52) at org.apache.dubbo.config.spring.context.OneTimeExecutionApplicationContextEventListener.onApplicationEvent(OneTimeExecutionApplicationContextEventListener.java:40) at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:172) at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:165) at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:139) at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:393) at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:347) at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:883) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:546) at org.springframework.context.annotation.AnnotationConfigApplicationContext.(AnnotationConfigApplicationContext.java:84) at org.apache.dubbo.samples.ProviderBootstrap.main(ProviderBootstrap.java:33)

[chickenlj]

是不是pom里少 dubbo-protocol-dubbo 依赖