今天學習springboot,使用idea建立專案。在選擇元件時添加了mysq 然後在第一次啟動的時候啟動報錯，錯誤資訊如下：

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APPLICATION FAILED TO START
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Description:
Failed to auto-configure a DataSource: 'spring.datasource.url' is not specified and no embedded datasource could be auto-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).

在多方查證後，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。

解決問題方法2：不用改動新增語句，注意專案檔案結構的正確性