org.hibernate.HibernateException: Connection cannot be null when 'hibernate.dialect' not set

这看起来很奇怪,因为我将hibernate方言设置如下：

p:databasePlatform="org.hibernate.dialect.MysqL5Dialect

有关更多信息,请参阅我的完整applicationContext.xml：

<?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:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.1.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd">


    <bean id="dataSource"
          class="org.springframework.jdbc.datasource.DriverManagerDataSource"
          p:driverClassName="com.MysqL.jdbc.Driver"
          p:url="jdbc:MysqL://localhost/room_management" p:username="root" p:password=""/>

    <bean id="entityManagerFactory"
          class="org.springframework.orm.jpa.LocalContainerEntityManagerfactorybean"
          p:dataSource-ref="dataSource" p:persistenceUnitName="RoomManagement">
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"
                  p:database="MysqL"
                  p:databasePlatform="org.hibernate.dialect.MysqL5Dialect"
                  p:showsql="true"/>
        </property>
    </bean>

    <bean id="transactionManager"
          class="org.springframework.orm.jpa.JpaTransactionManager"
          p:entityManagerFactory-ref="entityManagerFactory"/>

    <context:annotation-config/>


    <context:component-scan base-package="com.parisdescartes.roommanagement.*"/>

    <tx:annotation-driven/>

</beans>

所以,我决定在Meta-INF / persistence.xml文件中精确地使用Hibernate Dialect,这次是有效的.在这里我如何精确它：

<properties>
            <property name="hibernate.dialect"
                      value="org.hibernate.dialect.MysqL5Dialect"/>
</properties>

你知道为什么没有使用Spring配置设置Hibernate Dialect吗？