【方言】Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="2.0">
<persistence-unit name="userPU" transaction-type="RESOURCE_LOCAL">
<!--jpa的提供者-->
<provider>org.hibernate.ejb.HibernatePersistence</provider>
<properties>
<!--声明数据库连接的驱动-->
<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver"/>
<!--jdbc数据库的连接地址-->
<property name="hibernate.connection.url" value="jdbc:mysql://10.32.11.74:3306/jparest"/>
<property name="hibernate.connection.username" value="root"/>
<property name="hibernate.connection.password" value="123456"/>
<!--配置方言-->
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5Dialect"/>
<!--激活查询日志功能-->
<property name="hibernate.show_sql" value="true"/>
<!--优雅地输出Sql-->
<property name="hibernate.format_sql" value="true"/>
<!--添加一条解释型标注-->
<property name="hibernate.use_sql_comments" value="false"/>
<!--配置如何根据java模型生成数据库表结构,常用update,validate-->
<property name="hibernate.hbm2ddl.auto" value="update"/>
</properties>
</persistence-unit>
</persistence>

<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="showSql" value="${hibernate.showSql}" />
<property name="generateDdl" value="true" />

<property name="databasePlatform"
value="org.hibernate.dialect.MySQL5Dialect">
</property>
</bean>
</property>

<beans>
<bean id="entityManagerFactory"class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="generateDdl" value="true"/>
<property name="database" value="HSQL"/>
</bean>
</property>
<property name="persistenceUnitName" value="jpa.sample"/>
</bean>
<bean id="transactionManager"class="org.springframework.orm.jpa.JpaTransactionManager">
<property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>
<jdbc:embedded-database id="dataSource" type="HSQL"/>
<jpa:repositories base-package="org.springframework.data.jpa.example.repository.simple"/>
</beans>