hibernate异常，org.hibernate.MappingException: Unknown entity: com.yourcompany.struts.form.UserNameForm

和struts结合，com.yourcompany.struts.form.UserNameForm是formbean,报org.hibernate.MappingException: Unknown entity: com.yourcompany.struts.form.UserNameForm错误，这是hbm文件：
  <?xml version="1.0" encoding="UTF-8"?>
  <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "hibernate-mapping-3.0.dtd" >
  <hibernate-mapping>
  <class name="com.yourcompany.struts.form.UserNameForm" table="USER">
  <id name="id" column="id" type="long">
  <generator class="identity"></generator>
  </id>
  <property name="name" column="name" type="String"></property>
  <property name="password" column="password" ></property>
  </class>
  </hibernate-mapping>

------解决方法--------------------------------------------------------
没有建立映射     
  你的hibernate.cfg.xml 里面有没有把映射文件加进去?