Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Tue May 25 18:22:11 CST 2021
There was an unexpected error (type=Internal Server Error, status=500).
nested exception is org.apache.ibatis.exceptions.PersistenceException: ### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: 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. ### The error may exist in file [D:\D\XiaoBao\Chapter11\target\classes\mapper\mysql.xml] ### The error may involve com.course.getUserCount ### The error occurred while executing a query ### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: 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.