spring boot 连接mysql报错。配置数据源失败：未指定“url”属性，无法配置嵌入的数据源

报错信息：

Failed to configure a DataSource: 'url' attribute is not specified and no embedded datasource could be configured.

Reason: Failed to determine a suitable driver class

Action:

Consider the following:
	If you want an embedded database (H2, HSQL or Derby), please put it on the classpath.
	If you have database settings to be loaded from a particular profile you may need to activate it (no profiles are currently active).

配置信息：

#mysql配置
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=root
#可以不配置，spring boot 会尽可能的判断数据库类型，然后默认配置驱动类
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

依赖：

    mysql
    mysql-connector-java
    runtime


    org.springframework.boot
    spring-boot-starter-jdbc


   org.apache.commons
   commons-dbcp2

原因：找不到原因。

       数据库是真实存在，并且能连上的。没有办法，我从新建了一个项目然后用相同的配置就可以起来了。头疼，有哪位大神知道原因的麻烦告诉我，感激不尽。