SpringBoot启动异常：Reason: Failed to determine a suitable driver class

程式之前都运行正常，忽然一天运行报错：

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APPLICATION FAILED TO START
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Description:

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).

也不知道是什么原因，配置文件不起作用了，

所以在 Project Structure中查看一下 Modules，发现果然，src -> main -> resources这个文件夹，不是Resources的类型

修改其为 Resources，然后重新运行即可