JDBC鏈接Mysql失敗

錯誤信息：Error querying database.  Cause: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.

問題原因：新版本mysql數據庫（我是的時8.0.15， 具體mysql那個版本未知）更改了登錄用戶名和密碼的加密方式，老版本mysql 無法鏈接

解決方式：需要更新 mysql-connector-java 版本

<dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.15</version>
</dependency>

更新JDBC代碼后再次重連，繼續報錯

錯誤信息：Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.

問題原因： mysql 驅動 package 變動

解決方法： 修改JDBC 驅動為：com.mysql.cj.jdbc.Driver