java.lang.RuntimeException: java.lang.RuntimeException: java.sql.SQLException: The connection proper

sqoop问题：
java.lang.RuntimeException: java.lang.RuntimeException: java.sql.SQLException: The connection proper

---

sqoop import 
--connect "jdbc:mysql://localhost/employees?zeroDateTimeBehavior=CONVERT_TO_NULL" 
--table tablename
--username username
--password password
--m 1 
--target-dir /user/sqoop/tablename
--outdir java_files

请参考：
https://stackoverflow.com/questions/48436347/sqoop-import-error