急寻救助：Instantiation of bean failed怎么解决啊？

[lizhensnow]

log4j:WARN No appenders could be found for logger (org.springframework.context.support.ClassPathXmlApplicationContext).
log4j:WARN Please initialize the log4j system properly.
2010-6-18 11:46:42 com.microsoft.sqlserver.jdbc.AuthenticationJNI <clinit>
警告: Failed to load the sqljdbc_auth.dll
Exception in thread "main" org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'messageDao' defined in class path resource [applicationContext.xml]: Instantiation of bean failed; nested exception is org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springframework.orm.hibernate3.support.HibernateDaoSupport]: Is it an abstract class?; nested exception is java.lang.InstantiationException
Caused by: org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springframework.orm.hibernate3.support.HibernateDaoSupport]: Is it an abstract class?; nested exception is java.lang.InstantiationException
Caused by: java.lang.InstantiationException
at sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at org.springframework.beans.BeanUtils.instantiateClass(BeanUtils.java:85)
at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:61)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateBean(AbstractAutowireCapableBeanFactory.java:757)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:722)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:386)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:249)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:155)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:246)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:160)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:291)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:352)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:122)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:66)
at com.njcit.bookstore.Test.Test1.main(Test1.java:12)

这个错怎么解决啊？

还有，

spring配置文件（部分）：
<bean id="messageDao"
class="org.springframework.orm.hibernate3.support.HibernateDaoSupport"
abstract="false" lazy-init="default" autowire="default"
dependency-check="default">
<property name="sessionFactory">
<ref bean="sessionFactory" />
</property>
</bean>

我不懂class那句的作用

[amos1989]

抽象类?

[ronniegxq]

[Quote=引用 1 楼 tagalin 的回复:]

class应该是你实现了messageDao的类，HibernateDaoSupport是spring提供的虚拟类，class里的实现类要继承HibernateDaoSupport
[/Quote]
很正的解

[dream_1086]

一楼。。。。。。yes

[tagalin]

class应该是你实现了messageDao的类，HibernateDaoSupport是spring提供的虚拟类，class里的实现类要继承HibernateDaoSupport