The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

在链接数据库的时候，报错如下：

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

上网查，一般是设置超时时间，我这边设置超时时间是不管用的，敢肯定的是没有设置mysql白名单或者网络不通的问题。