springboot 學習問題
1. At least one JPA metamodel must be present!
 參考一：
 https://www.cnblogs.com/guwan/p/7901535.html
 https://blog.csdn.net/wangjie919/article/details/80347375
 

2. Error creating bean with name 'inMemoryDatabaseShutdownExecutor' defined in class path resource [org/springframework/boot/devtools/autoconfigure/DevToolsDataSourceAutoConfiguration.class]: Unsatisfied dependency expressed through method 'inMemoryDatabaseShutdownExecutor' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Hikari.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [com.zaxxer.hikari.HikariDataSource]: Factory method 'dataSource' threw exception; nested exception is org.springframework.boot.autoconfigure.jdbc.DataSourceProperties$DataSourceBeanCreationException: Failed to determine a suitable driver class

原因： 沒有對應的資料庫配置檔案，哈哈