如何配置hibernate.properties和hibernate.cfg.xml

我在hibernate.properties里用了：
hibernate.dialect net.sf.hibernate.dialect.MySQLDialect
hibernate.connection.driver_class org.gjt.mm.mysql.Driver
hibernate.connection.driver_class com.mysql.jdbc.Driver
hibernate.connection.url jdbc:mysql://localhost/test
hibernate.connection.username root
hibernate.connection.password
然后在程序里实现：
sessionFactory = new Configuration().addClass(Erm.class).buildSessionFactory();
Session s = sessionFactory.openSession();
Transaction t = s.beginTransaction();
Erm rem = new Erm();
rem.setId("001");
rem.setName("test");
s.save(rem);
t.commit();
s.close();

编译时也既然出现：
net.sf.hibernate.MappingException: Resource: com/hong/hibernate/test/Erm.hbm.xml not found

而我不知道我用了hibernate.properties，是不是还要用hibernate.cfg.xml，
但是我又不知道hibernate.cfg.xml里怎么配置？我把hibernate.properties放在classes的根目录下。
我只用了两个类：
Erm.java
public class Erm {
private String id;
private String name;

public void setId(String id){
this.id = id;
}
public String getId(){
return id;
}

public void setName(String name){
this.name = name;
}
public String getName(){
return name;
}
}

还有testErm.java
public class testErm {
protected static SessionFactory sessionFactory;
public static void main(String[] args) throws HibernateException{
sessionFactory = new Configuration().addClass(Erm.class).buildSessionFactory();
Session s = sessionFactory.openSession();
Transaction t = s.beginTransaction();
Erm rem = new Erm();
rem.setId("001");
rem.setName("test");
s.save(rem);
t.commit();
s.close();
}
}

还有一个Erm.hbm.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration
PUBLIC "-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-2.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Mapping files -->
<mapping resource="Erm.hbm.xml"/>

</session-factory>
</hibernate-configuration>

这是个很简单的例子，只是向表里添加一条记录，请问我哪里出了问题了？？

Erm.hbm.xml 要放在com/hong/hibernate/test/目录下，和你的Erm.class文件放在一起。

to chen56 ，是的，