[Dubbo-5049]support @Bean on Config class to config id as alias

[sonymoon]

as #5049 mentioned, when @Service(protocol = "dubbo1") is annotated on a class, the provider starts failed, dubbo1 is the id property of ProtocolConfig.

@Bean
  public ProtocolConfig config1() {
    ProtocolConfig config = new ProtocolConfig();
    config.setId("dubbo1");
    config.setName("dubbo");
    config.setPort(20880);
    return config;
  }

The failure cause is dubbo1 is not an name or alias of ProtocolConfig bean.

When using xml way:

<dubbo:application name="demo-provider"/>

    <dubbo:registry address="zookeeper://127.0.0.1:2181"/>

    <dubbo:protocol name="dubbo" id="dubbo1"/>

    <bean id="demoService" class="org.apache.dubbo.demo.provider.DemoServiceImpl"/>

    <dubbo:service interface="org.apache.dubbo.demo.DemoService" ref="demoService" protocol="dubbo1"/>

xml config with id property assigned with dubbo1, the provider starts successfully.

I think the annotation way should work fine as well.

My suggestion approach

Use spring extension interfaces, such as:

1. BeanDefinitionRegistry: can do the registry alias stuff
2. BeanPostProcessor: can do 1 after config beans's initialization by implementing method postProcessAfterInitialization, which is already implemented by class DubboConfigBindingBeanPostProcessor with an empty method.

Actually, @haiyang1985 has a PR #5051 solving this issue:
But I think using getBean in postProcessBeanDefinitionRegistry method cause the initialization of ProtocolConfig's bean too early (bean registry phase in spring) as @mercyblitz mentioned

[codecov-io]

Codecov Report

Merging #5063 into master will decrease coverage by 0.69%.
The diff coverage is 80%.

@@             Coverage Diff             @@
##             master    #5063     +/-   ##
===========================================
- Coverage     63.98%   63.29%   -0.7%     
+ Complexity      452      449      -3     
===========================================
  Files           769      790     +21     
  Lines         33206    35042   +1836     
  Branches       5237     5480    +243     
===========================================
+ Hits          21248    22180    +932     
- Misses         9533    10328    +795     
- Partials       2425     2534    +109

Impacted Files	Coverage Δ	Complexity Δ
...nnotation/DubboConfigBindingBeanPostProcessor.java	74.24% <80%> (+1.02%)	0 <0> (ø)	⬇️
...che/dubbo/remoting/transport/mina/MinaChannel.java	43.42% <0%> (-10.53%)	16% <0%> (-1%)
...ng/exchange/support/header/HeartbeatTimerTask.java	73.68% <0%> (-5.27%)	0% <0%> (ø)
.../apache/dubbo/qos/protocol/QosProtocolWrapper.java	65.85% <0%> (-4.88%)	0% <0%> (ø)
.../apache/dubbo/remoting/transport/AbstractPeer.java	58.69% <0%> (-4.35%)	0% <0%> (ø)
...he/dubbo/remoting/transport/netty/NettyServer.java	69.64% <0%> (-3.58%)	8% <0%> (-1%)
...e/dubbo/remoting/transport/netty/NettyChannel.java	52.27% <0%> (-3.41%)	19% <0%> (-1%)
.../rpc/protocol/dubbo/LazyConnectExchangeClient.java	56.47% <0%> (-2.36%)	0% <0%> (ø)
.../dubbo/remoting/transport/netty4/NettyChannel.java	64.77% <0%> (-2.28%)	0% <0%> (ø)
...he/dubbo/registry/multicast/MulticastRegistry.java	67.87% <0%> (-1.81%)	0% <0%> (ø)
... and 23 more

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[haiyang1985]

The PR have not solved my issue. When user defined ProtocolConfig as a spring bean , service annotation cannot get the dubbo bean id.

@Service(protocol = "dubbo1")
public class DubboDemoServiceImpl implements DubboDemoService {
}

@Configuration
public class DubboConfiguration {
  @Bean
  public ProtocolConfig getConfig() {
    ProtocolConfig config = new ProtocolConfig();
    config.setId("dubbo1");
    config.setName("dubbo");
    config.setPort(20770);
    return config;
  }
}

I've tried your solution in my local, still not able to get dubbo bean id.

***************************
APPLICATION FAILED TO START
***************************

Description:

A component required a bean named 'dubbo1' that could not be found.

[sonymoon]

Can you provider a GitHub address which can reproduce this?