1.啟動報Loading class com.mysql.jdbc.Driver'. This is deprecated. The new driver class iscom.mysql.cj.jdbc.Driver’. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.錯誤

2.訪問時報java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.

可以是在配置mysql時，沒有指定mysql的版本，採用預設的版本，預設的版本過高，本地版本低。因為在mysql5中，jdbc的驅動是com.mysql.jdbc.Driver，而mysql6以及以上是com.mysql.cj.jdbc.Driver。所以在配置時要配置mysql版本號，主要配置資料來源的驅動。

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.21</version>  **這裡指定匹配版本號**
        </dependency>
 

spring.datasource.url=jdbc:mysql://localhost:3306/database?useUnicode=true&characterEncoding=UTF-8&serverTimezone=UTC
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
**配置的驅動要和Mysql的版本一致**