采用
<prop key="hibernate.hbm2ddl.auto">create</prop>
根据文档，更新会更新现有架构。
简单来说，
validate: validate the schema, makes no changes to the database.update: update the schema.create: creates the schema, destroying previous data.create-drop: drop the schema at the end of the session.auto : Automatically validates or exports schema DDL to the database when the SessionFactory is created
