服务器未知运行时异常: nested exception is org.apache.ibatis.exceptions.PersistenceException: 
### Error querying database.  Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException
### The error may exist in file [D:\code\casic-metering\casic-metering-dao\target\classes\mapper\business\BusinessBoardMapper.xml]
### The error may involve com.casic.missiles.mapper.business.BusinessBoardMapper.selectCertificatesToday
### The error occurred while executing a query
### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException