强制休眠在删除和重新创建数据库之后创建表 [英] Force Hibernate To Create Tables After Dropping and Recreating database

问题描述

我正在用java 2 ee开发一个web应用程序。我也使用休眠和MySQL。
为了恢复备份文件，在我的应用程序中的某一点，我需要删除当前数据库并重新创建它，我这样做：

<$ p （连接）DriverManager.getConnection（jdbc：mysql：// localhost /？user = user& password = pass）; $ p> Connection conn =
Statement statement =（Statement）conn.createStatement（）;
statement.executeUpdate（DROP DATABASE tcs;）;
statement.executeUpdate（CREATE DATABASE tcs charset = utf8 collat​​e = utf8_persian_ci;）;


删除并重新创建后，我需要使用默认用户（spring security user）初始化数据库

  User admin = new User（）; 
 UserAuthority ROLE_USER = new UserAuthority（ROLE_USER）; 
 ROLE_USER.save（）; 
 admin.addUserAuthority（ROLE_USER）; 
 admin.setEnabled（true）; 
 
 admin.save（）; 
  

但在最后一行应用程序抛出这个异常

  Hibernate：插入角色（权限）值（？）
 [DEBUG] [16：19：17,734] [http-bio-8080-exec-10] NewPooledConnection ：367 com.mchange.v2.c3p0.impl.NewPooledConnection@bcbe33a处理一个throwable。 
 com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException：表'tcs.roles'不存在
  

我知道hibernate在启动时创建表，但在这种情况下，它无法在删除/重新创建后重新创建表，所以我如何强制hibernate再次创建表？
或假设是否有类似于 Hibernate.createTable（Class）？

解决方案对于未来的googlers：
它非常简单，毕竟，我只需要建立会话工厂，所以我添加了这一行，它的工作方式就像是魅力：

（）。buildSessionFactory（）;

注意 buildSessionFactory（）是在hibernate 4弃用，但我想你可以使用代码这里来做相同。

I am developing a web application with java 2 ee. I also use hibernate and mysql. in order to restore the backup file, in some point in my application i need to drop the current database and recreate it, i do it as follow :

    Connection conn = (Connection) DriverManager.getConnection("jdbc:mysql://localhost/?user=user&password=pass");
    Statement statement = (Statement) conn.createStatement();
    statement.executeUpdate("DROP DATABASE tcs;");
    statement.executeUpdate("CREATE DATABASE tcs charset=utf8 collate=utf8_persian_ci;");

after dropping and recreating i need to initialize database with default user (spring security user)

    User admin = new User();
    UserAuthority ROLE_USER = new UserAuthority("ROLE_USER");
    ROLE_USER.save();
    admin.addUserAuthority(ROLE_USER);
    admin.setEnabled(true);

    admin.save();

but at the last line application throws this exception

Hibernate: insert into roles (authority) values (?)
[DEBUG][16:19:17,734] [http-bio-8080-exec-10] NewPooledConnection:367  com.mchange.v2.c3p0.impl.NewPooledConnection@bcbe33a handling a throwable.
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table 'tcs.roles' doesn't exist

i know hibernate creates tables at startup but in this case it fails to recreate the tables after a drop/recreate , so how can i force hibernate to create tables again? or hypothetically is there something like Hibernate.createTable(Class) ?

解决方案

for future googlers : it was so simple after all , i just needed to build session factory so i added this line and it worked like charm :

new Configuration().configure().buildSessionFactory();

note that buildSessionFactory() is deprecated in hibernate 4 but i guess you can use the code here to do the same.

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