If you have database settings to be loaded from a particular profile you may

今天在写SpringBoot项目的时候遇到了以前没有碰到过的一个错误：

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2020-05-26 16:00:33.380 ERROR 12908 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

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).

问题是在我配置完yml的数据库连接文件后出现的，之前也有一个properties，只要把yml文件删除就没问题了，但是把properties文件删除就没用，所以我以为很纳闷，后来在查了一下资料以后发现有一个解决方案是 需要在启动类的@EnableAutoConfiguration或@SpringBootApplication中添加exclude = {DataSourceAutoConfiguration.class}，排除此类的autoconfig，我试着做了 问题真的解决了，但是原理还是不是很了解 ，把问题记录下来 ，后面再进行研究！

@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class SecurityApplication {

    public static void main(String[] args) {
        SpringApplication.run(SecurityApplication.class, args);
    }

}