SpringCloud整合Nacos启动报错:Injection of autowired dependencies failed； nested exception is java.lang.Ill

报错内容：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘memberServiceImpl’: Injection of autowired dependencies failed; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder ‘demo.userName’ in value “${demo.userName}”

问题原因：
默认情况下Nacos读取配置文件为properties结尾

解决方式：
在bootstrap.yml配置文件中指定配置文件格式为yml