Spring boot專案剛搭建好，啟動測試，出現Failed to configure a DataSource
今天新搭建了一個springboot+gradle框架，然而，剛搭建好執行的時候，就報了一個錯誤：
Error starting ApplicationContext. To display the conditions report re-run your application with ‘debug’ enabled.
2018-11-19 13:59:44.020 ERROR 1256 — [ 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).
問過度娘娘後，才知道，需要在啟動類的@EnableAutoConfiguration或@SpringBootApplication中新增exclude= {DataSourceAutoConfiguration.class}，排除此類的autoconfig。啟動以後就可以正常執行。
這是因為添加了資料庫元件，所以autoconfig會去讀取資料來源配置，而我新建的專案還沒有配置資料來源，所以會導致異常出現。
照著改過之後，再次執行，就可以了，親測。。。