这2种方式都可以实现不用persistence.xml文件，免去每个Entity都要在
persistence.xml
文件中配置的烦恼，但是这种方式
Entity实体类的主键字段注解@ID要放到 getXXX()方法上，否则不认。
方式1：
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerfactorybean">
<property name="packagesToScan" value="com.pilicat.data.entity" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter"/>
</property>
<property name="jpaProperties">
<props>
<prop key="hibernate.connection.driver_class">${jdbc.driverClassName}</prop>
<prop key="hibernate.connection.url">${jdbc.url}</prop>
<prop key="hibernate.connection.username">${jdbc.username}</prop>
<prop key="hibernate.connection.password">${jdbc.password}</prop>
<prop key="hibernate.c3p0.min_size">10</prop>
<prop key="hibernate.hbm2ddl.auto">true</prop>
<prop key="hibernate.dialect">${hibernate.dialect}</prop>
</props>
</property>
</bean>
方式2：
修改“LocalContainerEntityManagerfactorybean”的配置，如下：
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerfactorybean">
<property name="dataSource" ref="dataSource" />
<property name="persistenceXmlLocation" value="classpath:persistence-app.xml" />
<!--
<property name="persistenceUnitName" value="com.pilicat.data.entity" />-->
<property name="packagesToScan" value="com.pilicat.data.entity" />
<property name="jpaVendorAdapter">
<bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="databasePlatform" value="${hibernate.dialect}" />
<property name="generateDdl" value="true" />
</bean>
</property>
</bean>
