1 详细异常
ser class threw exception: java.sql.SQLException: The last packet successfully received from the server was 39,444 milliseconds ago. The last packet sent successfully to the server was 39,444 milliseconds ago. is longer than the server configured value of 'wait_timeout'. You should consider either expiring and/or testing connection validity before use in your application, increasing the server configured values for client timeouts, or using the Connector/J connection property 'autoReconnect=true' to a
2 解决方案
mysql 链接失效时间设置过短,导致(改到一个合适的时间,根据自己的应用程序)
SHOW GLOBAL VARIABLES LIKE '%timeout%'
SET GLOBAL wait_timeout=10000
SET GLOBAL wait_timeout=10000