Can't reach database server or port

SQLState - 08S01
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

 ==========解决============

开始以为是数据库的配置问题，但是用mysql -hlocalhost -uroot -p却可以正常连接。

后来百度搜索，说是需要加参数：useSSL=false

因为我的mysql是用的docker起的服务，仍然报错，不能连接。

后来把localhost改成本机IP地址解决了：

jdbc:mysql://192.168.1.34/confluence?useSSL=false

参考：

https://blog.csdn.net/xiongshengwu/article/details/46981101