解決報錯(Could not create connection to database server.)

org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory 

嘗試多種方法后發現是由於mysql驅動版本太低導致。

報錯，mysql版本是8.0.11，mysql-connector-java版本是5.1.31，后來把mysql-connector-java改為最新版運行成功。

<!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.15</version>
        </dependency>