SSH整合出现如下错误，求解？
log4j:WARN No appenders could be found for logger (org.springframework.context.support.ClassPathXmlApplicationContext).
log4j:WARN Please initialize the log4j system properly.
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [applicationContext.xml]: Invocation of init method failed; nested exception is org.hibernate.MappingException: Association references unmapped class: com.lkw.bean.Emp1
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1403)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:513)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:450)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:290)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:287)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:189)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:545)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:871)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:423)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
at com.lkw.dao.Main.main(Main.java:13)
Caused by: org.hibernate.MappingException: Association references unmapped class: com.lkw.bean.Emp1
at org.hibernate.cfg.HbmBinder.bindCollectionSecondPass(HbmBinder.java:2399)
at org.hibernate.cfg.HbmBinder$CollectionSecondPass.secondPass(HbmBinder.java:2678)
at org.hibernate.cfg.CollectionSecondPass.doSecondPass(CollectionSecondPass.java:66)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1177)
at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1162)
at org.springframework.orm.hibernate3.LocalSessionFactoryBean.buildSessionFactory(LocalSessionFactoryBean.java:717)
at org.springframework.orm.hibernate3.AbstractSessionFactoryBean.afterPropertiesSet(AbstractSessionFactoryBean.java:211)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1460)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1400)
... 12 more
------最佳解决方案--------------------
WARN No appenders co