服务器未知运行时异常: 
### Error querying database.  Cause: com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet successfully received from the server was 19,200 milliseconds ago.  The last packet sent successfully to the server was 1,579,092 milliseconds ago.
### The error may exist in class path resource [com/casic/missiles/modular/system/dao/mapping/DeptMapper.xml]
### The error may involve defaultParameterMap
### The error occurred while setting parameters
### SQL: select id,pid as pId,simple_name as name,id as "deptId",         (         CASE         WHEN (pId = '0' OR pId IS NULL) THEN         'true'         ELSE         'false'         END         ) as isOpen from sys_dept          WHERE  del_flag = '0'          ORDER BY pid,num
### Cause: com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet successfully received from the server was 19,200 milliseconds ago.  The last packet sent successfully to the server was 1,579,092 milliseconds ago.
; Communications link failure

The last packet successfully received from the server was 19,200 milliseconds ago.  The last packet sent successfully to the server was 1,579,092 milliseconds ago.; nested exception is com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet successfully received from the server was 19,200 milliseconds ago.  The last packet sent successfully to the server was 1,579,092 milliseconds ago.