Table of contents
specific error message
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 233 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.
Some programs on the Internet
Increase the wait_timeout of mysql
Use autoReconnect=true&failOverReadOnly=false, (only valid for versions before mysql 4)
The time in the error message of the above solutions is generally very large, such as
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 1,548,635,756,564 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.
But my error is not a timeout, because wait_timeout is 8 hours by default, and the time in the error message is only 233ms.
solution
In this case you can try to
The Driver in the configuration file is set to com.mysql.cj.jdbc.Driver
com.mysql.jdbc.Driver is mybatis-connection-java 5 and below
com.mysql.cj.jdbc.Driver is mybatis-connection-Java 6 and above
spring:
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
mysql dependency in pom can be set to version 6+
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.28</version>
</dependency>
After the modification, the project can run normally.