Flink程序异常--CommunicationsException: The last packet successfully received from the server was

一、异常截图

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: The last packet successfully received from the server was 46,912,998 milliseconds ago.  The last packet sent successfully to the server was 46,913,003 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 avoid this problem.
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

二、原因

连接数据库超时

三、解决方法

解决方法1：使用连接池定时刷新服务器时间戳

解决方法2：flink连接mysql时指定autoReconnect=true

即使在创建Mysql时url中加入了autoReconnect=true参数,一但这个连接两次访问数据库的时间超出了服务器端 wait_timeout的时间限制