Could not open Hibernate Session for transaction

问题描述：

首次访问网站报错误HTTP Status 500 - Could not open Hibernate Session for transaction; nested exception is org.hibernate.TransactionException: JDBC begin transaction failed:，刷新后正常.

解决方案：
给jdbc url加autoReconnect=true
找到数据库连接的jdbc url，我的在db.properties文件内，把下面这行加到url后面：

?&useUnicode=true&characterEncoding=utf-8&autoReconnect=true