问题：本地访问一切正常，部署到阿里云之后出现mybatis访问数据库失败，反正就是无法连接到数据库,jdbc连接失败。
{
"timestamp": "2023-04-18T14:03:49.341+0000",
"status": 500,
"error": "Internal Server Error",
"message": "nested exception is org.apache.ibatis.exceptions.PersistenceException: \n### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure\n\nThe last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.\n### The error may exist in com/campus/dao/QuestionMapper.java (best guess)\n### The error may involve com.campus.dao.QuestionMapper.selectAll\n### The error occurred while executing a query\n### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure\n\nThe last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.",
"path": "/question/getAllList"
}
解决：在数据库配置最后地方加这个：
serverTimezone=UTC&useSSL=false
标签：jdbc,数据库,server,访问,error,mybatis,com,### From： https://www.cnblogs.com/lxpblogs/p/17331450.html