Dubbo学习：provider、consumer、dubbo-admin、dubbo-monitor
provider：服务提供者，部署方式见%root_path%/dubbo-deploy.txt
consumer：服务提供者，部署方式见%root_path%/dubbo-deploy.txt
dubbo-admin:管控后台，部署方式见%root_path%/dubbo-admin.txt
dubbo-monitor：监控中心，部署方式见%root_path%/dubbo-monitor.txt