The last packet sent successfully to the server was 0 milliseconds ago.

问题：The last packet sent successfully to the server was 0 milliseconds ago.

解决：出现错误的情况很多，我是因为没有关闭ssl

方法：

spring.datasource.url=jdbc:mysql://10.16.32.80:3306/testdb?useSSL=false
spring.datasource.username=root
spring.datasource.password=123456

参考：

https://blog.csdn.net/apachesolr/article/details/113766949