使用public ip时，Java MYSQL连接失败

Question

我的程序在使用我的公共IP时拒绝连接到我的mysql服务器，我打开了它所连接的端口，但我仍然得到了一些连接功能。

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.

这是我得到的错误消息，您可以在下面找到

的代码

Connection conn;
                String dbuser ="usrname";
                String dbpassw = "pass";
                String databaseName = "dbname";

                String url = "jdbc:mysql://"MY IP HERE":3306/"+databaseName;

                Class.forName("com.mysql.jdbc.Driver");
                conn = DriverManager.getConnection(url,dbuser,dbpassw);
                Statement st = conn.createStatement();

我使用了你从whatsmyip网站获得的ip。