解决Mysql ‘The last packet successfully received from the server was xxx milliseconds ago‘ 问题

springboot + druid + mysql 在查询某些比较耗时的sql会报错

报错信息：

com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet successfully received from the server was 10,010 milliseconds ago. The last packet sent successfully to the server was 10,010 milliseconds ago.
    at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
    at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
    at com.mysql.cj.jdbc.ClientPreparedStatement.executeInternal(ClientPreparedStatement.java:953)
    at com.mysql.cj.jdbc.ClientPreparedStatement.execute(ClientPreparedStatement.java:371)
......

解决方法是在datasource.url后面socketTimeout参数配置，这里配置了30000

例：

...
datasource:
  driver-class-name: com.mysql.cj.jdbc.Driver
  url: jdbc:mysql://localhost:3306/xxx?xxx&socketTimeout=30000
  username: 
  password:
...