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Apache Dubbo Component

Java Samples (apache/dubbo-samples)

Dubbo Version

Dubbo 3.3.4, SpringBoot 2.7.18, Corretto 1.8.0_452

Steps to reproduce this issue

Modify the samples code: ```[java] /** * stub-consumer/StubConsumer * / @DubboReference(check=false, stub="org.apache.dubbo.samples.stub.DemoServiceStub", onconnect = "print", interfaceName = "org.apache.dubbo.samples.stub.DemoService") private DemoService demoService;

```[stub-interface]
/**
 * stub-interface/DemoServiceStub
 * /

    public void print() {
        logger.info("onconnect.");
    }

then start zk, provider, consumer. and consumer print error log:

17:25:50.205 |-ERROR [main] pc.proxy.wrapper.StubProxyFactoryWrapper:    -|  [DUBBO] export a stub service error., dubbo version: 3.3.4, current host: 192.168.31.200, error code: 3-2. This may be caused by , go to https://dubbo.apache.org/faq/3/2 to find instructions. 
java.lang.IllegalStateException: No such extension org.apache.dubbo.rpc.Protocol by name consumer, no related exception was found, please check whether related SPI module is missing.
    at org.apache.dubbo.common.extension.ExtensionLoader.findException(ExtensionLoader.java:768) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.common.extension.ExtensionLoader.createExtension(ExtensionLoader.java:775) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.common.extension.ExtensionLoader.getExtension(ExtensionLoader.java:575) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.common.extension.ExtensionLoader.getExtension(ExtensionLoader.java:549) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.rpc.Protocol$Adaptive.export(Protocol$Adaptive.java) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.rpc.proxy.wrapper.StubProxyFactoryWrapper.export(StubProxyFactoryWrapper.java:139) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.rpc.proxy.wrapper.StubProxyFactoryWrapper.getProxy(StubProxyFactoryWrapper.java:99) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.rpc.ProxyFactory$Adaptive.getProxy(ProxyFactory$Adaptive.java) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.config.ReferenceConfig.createProxy(ReferenceConfig.java:522) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.config.ReferenceConfig.init(ReferenceConfig.java:383) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.config.ReferenceConfig.get(ReferenceConfig.java:244) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.config.utils.SimpleReferenceCache.get(SimpleReferenceCache.java:140) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.config.deploy.DefaultModuleDeployer.lambda$referServices$6(DefaultModuleDeployer.java:567) ~[dubbo-3.3.4.jar:3.3.4]
    at java.util.concurrent.ConcurrentHashMap$ValuesView.forEach(ConcurrentHashMap.java:4705) ~[?:1.8.0_452]
    at org.apache.dubbo.config.deploy.DefaultModuleDeployer.referServices(DefaultModuleDeployer.java:539) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.config.deploy.DefaultModuleDeployer.startSync(DefaultModuleDeployer.java:186) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.config.deploy.DefaultModuleDeployer.start(DefaultModuleDeployer.java:159) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.config.spring.context.DubboDeployApplicationListener.onContextRefreshedEvent(DubboDeployApplicationListener.java:167) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.config.spring.context.DubboDeployApplicationListener.onApplicationEvent(DubboDeployApplicationListener.java:153) ~[dubbo-3.3.4.jar:3.3.4]
    at org.apache.dubbo.config.spring.context.DubboDeployApplicationListener.onApplicationEvent(DubboDeployApplicationListener.java:52) ~[dubbo-3.3.4.jar:3.3.4]
    at org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener(SimpleApplicationEventMulticaster.java:178) ~[spring-context-5.3.31.jar:5.3.31]
    at org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener(SimpleApplicationEventMulticaster.java:171) ~[spring-context-5.3.31.jar:5.3.31]
    at org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent(SimpleApplicationEventMulticaster.java:145) ~[spring-context-5.3.31.jar:5.3.31]
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:429) ~[spring-context-5.3.31.jar:5.3.31]
    at org.springframework.context.support.AbstractApplicationContext.publishEvent(AbstractApplicationContext.java:386) ~[spring-context-5.3.31.jar:5.3.31]
    at org.springframework.context.support.AbstractApplicationContext.finishRefresh(AbstractApplicationContext.java:949) ~[spring-context-5.3.31.jar:5.3.31]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:594) ~[spring-context-5.3.31.jar:5.3.31]
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:732) ~[spring-boot-2.7.18.jar:2.7.18]
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:409) ~[spring-boot-2.7.18.jar:2.7.18]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:308) ~[spring-boot-2.7.18.jar:2.7.18]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1300) ~[spring-boot-2.7.18.jar:2.7.18]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1289) ~[spring-boot-2.7.18.jar:2.7.18]
    at org.apache.dubbo.samples.stub.consumer.StubConsumer.main(StubConsumer.java:44) ~[classes/:?]

What you expected to happen

Consumer can work normally

Anything else

No response

Are you willing to submit a pull request to fix on your own?

  • [ ] Yes I am willing to submit a pull request on my own!

Code of Conduct

Comment From: fantiq

Set protocol parameters on annotations，like this:

@DubboReference(check=false,
            protocol="dubbo",
            stub="org.apache.dubbo.samples.stub.DemoServiceStub",
            onconnect = "print",
            interfaceName = "org.apache.dubbo.samples.stub.DemoService")
    private DemoService demoService;

Comment From: kbac001

Set protocol parameters on annotations，like this:

@DubboReference(check=false, protocol="dubbo", stub="org.apache.dubbo.samples.stub.DemoServiceStub", onconnect = "print", interfaceName = "org.apache.dubbo.samples.stub.DemoService") private DemoService demoService;

Thanks a lot it worked, but why? I have defined dubbo.consumer.protocal: dubbo in application.yml but it doesn't work.

Comment From: fantiq

Set protocol parameters on annotations，like this: @DubboReference(check=false, protocol="dubbo", stub="org.apache.dubbo.samples.stub.DemoServiceStub", onconnect = "print", interfaceName = "org.apache.dubbo.samples.stub.DemoService") private DemoService demoService;

Thanks a lot it worked, but why? I have defined dubbo.consumer.protocal: dubbo in application.yml but it doesn't work.

can u please provider a complete example?

Comment From: kbac001

Set protocol parameters on annotations，like this: @DubboReference(check=false, protocol="dubbo", stub="org.apache.dubbo.samples.stub.DemoServiceStub", onconnect = "print", interfaceName = "org.apache.dubbo.samples.stub.DemoService") private DemoService demoService;

Thanks a lot it worked, but why? I have defined dubbo.consumer.protocal: dubbo in application.yml but it doesn't work.

can u please provider a complete example?

Sorry I don’t have more examples, but let me try to explain. From what I understand, if the protocol field isn’t set in @DubboReference , Dubbo will use the value from the config file — like dubbo.consumer.protocol or dubbo.protocol.name . And that works fine in most cases when stub.event is not involved.(In this issue, when I use onconnect , it automatically sets stub.event to true .)

And that’s where my question comes in. Why is stub.event treated differently? When I use onconnect or ondisconnect , why do I have to explicitly set the protocol field in @DubboReference for it to work? It’s not really explained in the official docs, so I’m not sure if this is expected behavior or a bug.

Comment From: fantiq

Set protocol parameters on annotations，like this: @DubboReference(check=false, protocol="dubbo", stub="org.apache.dubbo.samples.stub.DemoServiceStub", onconnect = "print", interfaceName = "org.apache.dubbo.samples.stub.DemoService") private DemoService demoService;

Thanks a lot it worked, but why? I have defined dubbo.consumer.protocal: dubbo in application.yml but it doesn't work.

can u please provider a complete example?

Sorry I don’t have more examples, but let me try to explain. From what I understand, if the protocol field isn’t set in @DubboReference , Dubbo will use the value from the config file — like dubbo.consumer.protocol or dubbo.protocol.name . And that works fine in most cases when stub.event is not involved.(In this issue, when I use onconnect , it automatically sets stub.event to true .)

And that’s where my question comes in. Why is stub.event treated differently? When I use onconnect or ondisconnect , why do I have to explicitly set the protocol field in @DubboReference for it to work? It’s not really explained in the official docs, so I’m not sure if this is expected behavior or a bug.

the correct configuration item is dubbo.consumer.protocol: dubbo. You can use it in the configuration file instead of setting it in the annotations.

If you have set the onconnect or ondisconnect options，proxy clients need to perform service export to listen for local network events, the export process need the protocol value.

can look at org.apache.dubbo.rpc.proxy.wrapper.StubProxyFactoryWrapper#getProxy(org.apache.dubbo.rpc.Invoker<T>, boolean) and org.apache.dubbo.remoting.exchange.support.ExchangeHandlerAdapter#invoke