spring3.2+hibernate4.1.8集成出现问题 400 请求报错

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
                           http://www.springframework.org/schema/beans/spring-beans-3.2.xsd
                           http://www.springframework.org/schema/aop 
                           http://www.springframework.org/schema/aop/spring-aop-3.2.xsd
                           http://www.springframework.org/schema/context 
                           http://www.springframework.org/schema/context/spring-context-3.2.xsd
                           http://www.springframework.org/schema/tx 
                           http://www.springframework.org/schema/tx/spring-tx-3.2.xsd">
	<!-- DI -->
	<context:annotation-config></context:annotation-config>

	<!-- datasource -->
	<bean id="datasource" 	class="org.springframework.jdbc.datasource.DriverManagerDataSource">
		<property name="driverClassName" value="com.mysql.jdbc.Driver" />
		<property name="url" value="jdbc:mysql://localhost:3306/test" />
		<property name="username" value="root" />
		<property name="password" value="root" />
	</bean>
	<!--sessionFactory  -->
	<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
		<property name="configLocation">
			<value>classpath:hibernate/hibernate.cfg.xml</value>
		</property>
	</bean>
	<!-- transactionManager -->
	<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
			<property name="sessionFactory">
				<ref bean="sessionFactory"/>
			</property>
	</bean>
</beans>

事务注入报错,测试取transactionManager的时候报下面错误. 去掉下面几行取sessionFactory时正常可以取到。求解释～

<!-- transactionManager -->
	<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
			<property name="sessionFactory">
				<ref bean="sessionFactory"/>
			</property>
	</bean>

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager' defined in class path resource [spring/db-applicationContext.xml]: Invocation of init method failed; nested exception is org.hibernate.service.UnknownUnwrapTypeException: Cannot unwrap to requested type [javax.sql.DataSource] at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1486) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:524) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:461) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:607) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479) at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139) at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83) at com.vooctj.test.TestSessionFactory.testSession(TestSessionFactory.java:14) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15) at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42) at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20) at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68) at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222) at org.junit.runners.ParentRunner.run(ParentRunner.java:300) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) Caused by: org.hibernate.service.UnknownUnwrapTypeException: Cannot unwrap to requested type [javax.sql.DataSource] at org.hibernate.service.jdbc.connections.internal.DriverManagerConnectionProviderImpl.unwrap(DriverManagerConnectionProviderImpl.java:91) at org.springframework.orm.hibernate4.SessionFactoryUtils.getDataSource(SessionFactoryUtils.java:91) at org.springframework.orm.hibernate4.HibernateTransactionManager.afterPropertiesSet(HibernateTransactionManager.java:252) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1545) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1483) ... 35 more