Dubbo + Nacos 服务启动报错，返回unknown user!

1、由于开启了nacos的安全认证，修改了nacos的application.properties

nacos.core.auth.enabled=true

2、错误信息如下：

Caused by: com.alibaba.nacos.api.exception.NacosException: Request nacos server failed: 
	at com.alibaba.nacos.client.naming.remote.gprc.NamingGrpcClientProxy.requestToServer(NamingGrpcClientProxy.java:279) ~[nacos-client-2.0.3.jar:na]
	at com.alibaba.nacos.client.naming.remote.gprc.NamingGrpcClientProxy.doRegisterService(NamingGrpcClientProxy.java:129) ~[nacos-client-2.0.3.jar:na]
	at com.alibaba.nacos.client.naming.remote.gprc.NamingGrpcClientProxy.registerService(NamingGrpcClientProxy.java:115) ~[nacos-client-2.0.3.jar:na]
	at com.alibaba.nacos.client.naming.remote.NamingClientProxyDelegate.registerService(NamingClientProxyDelegate.java:95) ~[nacos-client-2.0.3.jar:na]
	at com.alibaba.nacos.client.naming.NacosNamingService.registerInstance(NacosNamingService.java:145) ~[nacos-client-2.0.3.jar:na]
	at org.apache.dubbo.registry.nacos.NacosNamingServiceWrapper.registerInstance(NacosNamingServiceWrapper.java:57) ~[dubbo-3.0.2.1.jar:3.0.2.1]
	at org.apache.dubbo.registry.nacos.NacosRegistry.doRegister(NacosRegistry.java:170) ~[dubbo-3.0.2.1.jar:3.0.2.1]
	... 42 common frames omitted
Caused by: com.alibaba.nacos.api.exception.NacosException: unknown user!
	at com.alibaba.nacos.client.naming.remote.gprc.NamingGrpcClientProxy.requestToServer(NamingGrpcClientProxy.java:271) ~[nacos-client-2.0.3.jar:na]
	... 48 common frames omitted

3、 pom.xml 依赖配置如下：

	
        1.8
        UTF-8
        UTF-8
        2.3.6.RELEASE
        3.0.2.1
        2.0.3
    
    
    
        
            
            
                org.springframework.boot
                spring-boot-dependencies
                ${spring-boot.version}
                pom
                import
            
        
    

	
        
        
            org.springframework.boot
            spring-boot-starter-web
        

        
        
            org.apache.dubbo
            dubbo-spring-boot-starter
            ${dubbo.version}
        
        
        
            org.apache.dubbo
            dubbo-registry-nacos
            ${dubbo.version}
        
        
            com.alibaba.nacos
            nacos-client
            ${nacos.version}
        
    	

4、application.yml 配置内容如下：

spring:
  application:
    name: dubbo-demo-provider
  jackson:
    time-zone: GMT+8
    date-format: yyyy-MM-dd HH:mm:ss

dubbo:
  application:
    name: dubbo-demo-provider
    # 禁用QOS同一台机器可能会有端口冲突现象
    qos-enable: false
    qos-accept-foreign-ip: false
  scan:
    # 配置接口扫描包
    base-packages: tm.ucp.service
  protocol:
    # 协议类型
    name: dubbo
    port: 8888
  registry:
    protocol: dubbo
    address: nacos://localhost:8848?username=${username}&password=${password}
    timeout: 3000
    # 默认【public】 配置 namespace
    parameters:
      namespace: eec62008-6264-4e6e-aee8-bebb1c26a8ab

解决方法：
由于dubbo的源码中发现 username、paasword并没有实际用到，
而在 RegistryConfig 类中发现 address属性值中，对username、password值进行了处理

故采用如下方法进行配置

dubbo:
  registry:
     address: nacos://localhost:8848?username=${username}&password=${password}

配置文件参考：
https://github.com/apache/dubbo-spring-boot-project/tree/master/dubbo-spring-boot-samples/registry-samples

https://github.com/apache/dubbo/issues/5956

至此已成功解决，写的不好，望各位指正！！！