本地访问正常，部署之后出现mybatis访问数据库失败

　　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"
}