spring boot啓動報錯：
springboot項目啓動時，如果沒有配置數據庫配置，啓動時會拋出如下異常。
2018-06-04 11:18:39.153 INFO 2660 --- [ main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-06-04 11:18:39.435 WARN 2660 --- [ main] ationConfigEmbeddedWebApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Tomcat.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.apache.tomcat.jdbc.pool.DataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Cannot determine embedded database driver class for database type NONE. If you want an embedded database please put a supported one on the classpath. If you have database settings to be loaded from a particular profile you may need to active it (no profiles are currently active).
2018-06-04 11:18:39.441 INFO 2660 --- [ main] utoConfigurationReportLoggingInitializer :
Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2018-06-04 11:18:39.444 ERROR 2660 --- [ main] o.s.b.d.LoggingFailureAnalysisReporter :
***************************
APPLICATION FAILED TO START
***************************
Description:
Cannot determine embedded database driver class for database type NONE
Action:
If you want an embedded database please put a supported one on the classpath. If you have database settings to be loaded from a particular profile you may need to active it (no profiles are currently active).
2. 原因
@SpringBootApplication = (默認屬性)@Configuration + @EnableAutoConfiguration + @ComponentScan。springboot會自動注入數據源，而你卻沒有配，所以他就拋出該異常。
3. 如何不配
如果你只是簡單的想建個項目，並不需要數據庫支持，那麼你可以讓他不去注入數據源。
// 一般你啓動springboot項目，都會寫一個有@SpringBootApplication註解的類
// 你在這個註解中添加exclude={DataSourceAutoConfiguration.class,HibernateJpaAutoConfiguration.class}
// 即可無數據庫運行
@SpringBootApplication(exclude={DataSourceAutoConfiguration.class,HibernateJpaAutoConfiguration.class})