spring框架 调用druid中间件 时报这个错：
MetaDataAccessException: Could not get Connection for extracting meta-data; nested exception is org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is java.sql.SQLException: 发生语法错误。

报错原因1：gbase8s不支持select 1这种语法，应该改成select 1 from dual;

报错原因2：druid没加validationQuery， druid加上validationQuery就可以了