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

在連接數據庫的時候，報錯以下：

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

上網查，通常是設置超時時間，我這邊設置超時時間是無論用的，敢確定的是沒有設置mysql白名單或者網絡不通的問題。