请问老师Unknown entity: cqu.edu.entity.Students怎么解决呢

Question

测试类：

@Test

public void testSaveStudent(){

Configuration cfg = new Configuration();

        cfg.configure();

Session session = MyHibernateSessionFactory.getSessionFactory().getCurrentSession();

session.beginTransaction();

Transaction tx=session.beginTransaction();

       // cfg.addClass(cqu.edu.entity.Students.class); 

Students student1=new Students("S0000001","张三","男",new Date(),"重庆");

Students student2=new Students("S0000002","李四","男",new Date(),"海南");

Students student3=new Students("S0000003","王五","男",new Date(),"四川");

session.save(student1);

session.save(student2);

session.save(student3);

tx.commit();

}

hibernate.cfg.xml文件：

<?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 > 

     <property name ="connection.username">root</property>

     <property name ="connection.password">123456</property>

     <property name= "connection.driver_class">com.mysql.jdbc.Driver </property >      <!-- 驱动路径 --> 

     <property name= "connection.url">jdbc:mysql://127.0.0.1:3306/students_database?useUnicode=true&amp;characterEncoding=UTF-8</property ><!-- 连接数据库字符串 -->  

     <property name= "hibernate.dialect">org.hibernate.dialect.MySQLDialect</property > 

     <property name ="show_sql">true</property>     <!-- 显示SQL语句 -->  

     <property name ="format_sql">true</property>  

     <property name ="hbm2ddl.auto">update</property>    

            <!-- 配置使用session.getCurrentSession()方法 -->

     <property name= "hibernate.current_session_context_class" >thread</property > 

     <property name="javax.persistence.validation.mode">none</property> 

     <!-- hbm.xml -->

     <mapping resource ="cqu/edu/entity/Users.hbm.xml"/>

<mapping resource ="cqu/edu/entity/yStudents.hbm.xml"/>

    

    </session-factory > 

</hibernate-configuration>   

相应的Students.hbm.xml文件：

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE hibernate-mapping PUBLIC   

    "-//Hibernate/Hibernate Mapping DTD 3.0//EN"  

    "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">

<hibernate-mapping>

   <class name="cqu.edu.entity.Students" table="STUDENTS">

   <id name="sid" type="java.lang.String"  length="8">

   <generator class="assigned"/>

   </id>

   <property name="sname" type="java.lang.String"></property>

   <property name="gender" type="java.lang.String"></property>

   <property name="birthday" type="java.util.Date"></property>

   <property name="address" type="java.lang.String"></property>

   

   </class>

</hibernate-mapping>  

谢谢！