Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set
这是为什么？

设置hibernate.dialect了吗？

设置了的！
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>

这是获得sessionFactory
public SessionFactory getSession() {
Configuration cfg = new Configuration();
return cfg.buildSessionFactory(new StandardServiceRegistryBuilder().build());
}
这是hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost/hibernate</property>
<property name="connection.username">root</property>
<property name="connection.password">123456</property>
<!-- JDBC connection pool (use the built-in) -->
<!-- <property name="connection.pool_size">1</property> -->
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- 格式化SQL语句 -->
<property name="format_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">update</property>
<!-- <mapping class="com.suse.edu.model.Group"/>
<mapping resource="com/suse/edu/model/User.hbm.xml"/> -->
<mapping class="com.suse.edu.model.Student"/>
<mapping class="com.suse.edu.model.Question"/>
<mapping class="com.suse.edu.model.Answer"/>
</session-factory>
</hibernate-configuration>

Configuration configuration = new Configuration().configure();
ServiceRegistry serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry);
Session session = sessionFactory.openSession();
session.beginTransaction();
session.getTransaction().commit();
session.close();
sessionFactory.close();
亲测可用，4.3.4.Final。你再试试吧。

追新版是要付出点代价的！

<property name="age" column="email" type="int" />
我这一句话写错了，结果Hibernate4.3就alter 了我的表，新建了一个column，叫email，真是太智能了。

RDBMS Dialect
MySQL org.hibernate.dialect.MySQLDialect
MySQL with InnoDB org.hibernate.dialect.MySQLInnoDBDialect
MySQL with MyISAM org.hibernate.dialect.MySQLMyISAMDialect
MySQL5 org.hibernate.dialect.MySQL5Dialect
MySQL5 with InnoDB org.hibernate.dialect.MySQL5InnoDBDialect
mysql版本好像需要用不同的dialect，mysql5的需要用的dialect有改动，你上面写得是：
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>