急求高手回答（启动Tomcat时，发生创建sessionFactory异常）是何原因
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in file [D:\tomcat5.5\webapps\oa1.myeclipse.bak\WEB-INF\classes\applicationContext-common.xml]: Invocation of init method failed; nested exception is org.hibernate.MappingException: Could not determine type for: com.oa.model.Organization, for columns: [org.hibernate.mapping.Column(org)]
Caused by: 
org.hibernate.MappingException: Could not determine type for: com.oa.model.Organization, for columns: [org.hibernate.mapping.Column(org)]

------解决方案--------------------
找不到映射类
com.oa.model.Organization