數據庫訪問異常，獲取不到連接。
Caused by: org.apache.ibatis.exceptions.PersistenceException:?
### Error querying database. ?Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Connections could not be acquired from the underlying database!
###
2017-05-04
已解決，maven中mysql依賴有問題。