使用mybatis逆向工程时，连接数据库出现如下错误：
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.
查阅资料发现，数据库连接的url需要改为connectionURL="jdbc:mysql://localhost:3306/ssm?useSSL=false"，即在曾经的url后面添加useSSL=false即可