注解的力量 -----Spring 2.5 JPA hibernate 使用方法的点滴整理（二）：进一步消除 hibernate.cfg.xml

通过上面一步骤。我们简化了hibernate中扰人的 xxxxx.hbm.xml文件。那么是否可以再进行简化呢？

那么，我们在这一步骤的目的，就是把整个 hibernate.cfg.xml都给简化了。

 

依然是利用注解注入的方式。通过jpa 我们可以把 hibernate.cfg.xml中那些 mapping classes再次简化与无形。

 

1. 在applicationContext.xml中进行如下配置
   
   1. <?xml version="1.0" encoding="UTF-8"?>
   2. <beans xmlns="http://www.springframework.org/schema/beans"
   3.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   4.     xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"
   5.     xmlns:tx="http://www.springframework.org/schema/tx">
   8.     <bean id="entityManagerFactory"
   9.         class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
   10.         <property name="persistenceUnitName" value="testerPU" />
   11.     </bean>
   12.     <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
   13.         <property name="entityManagerFactory" ref="entityManagerFactory" />
   14.     </bean>
   16.     <tx:annotation-driven transaction-manager="transactionManager" />
   18.     <bean id="transactionInterceptor"
   19.         class="org.springframework.transaction.interceptor.TransactionInterceptor">
   20.         <!-- 事务拦截器bean需要依赖注入一个事务管理器 -->
   21.         <property name="transactionManager">
   22.             <ref local="transactionManager" />
   23.         </property>
   24.         <property name="transactionAttributes">
   25.             <!-- 下面定义事务（指service里面的方法）传播属性 -->
   26.             <props>
   27.                 <prop key="insert*">PROPAGATION_REQUIRED</prop>
   28.                 <prop key="update*">PROPAGATION_REQUIRED</prop>
   29.                 <prop key="save*">PROPAGATION_REQUIRED</prop>
   30.                 <prop key="add*">PROPAGATION_REQUIRED</prop>
   31.                 <prop key="update*">PROPAGATION_REQUIRED</prop>
   32.                 <prop key="remove*">PROPAGATION_REQUIRED</prop>
   33.                 <prop key="delete*">PROPAGATION_REQUIRED</prop>
   34.                 <prop key="get*">PROPAGATION_REQUIRED,readOnly
   35.                 </prop>
   36.                 <prop key="find*">PROPAGATION_REQUIRED,readOnly
   37.                 </prop>
   38.                 <prop key="load*">PROPAGATION_REQUIRED,readOnly
   39.                 </prop>
   40.                 <prop key="change*">PROPAGATION_REQUIRED</prop>
   41.                 <prop key="count*">PROPAGATION_REQUIRED</prop>
   42.                 <prop key="*">PROPAGATION_REQUIRED</prop>
   43.             </props>
   44.         </property>
   45.     </bean>
   46.     <!-- 定义自动代理BeanNameAutoProxyCreator -->
   47.     <bean id="beanNameAutoProxyCreator"
   48.         class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
   49.         <!-- 指定对满足哪些bean name的bean自动生成业务代理 -->
   50.         <property name="beanNames">
   51.             <list>
   52.                 <value>*Service</value>
   53.             </list>
   54.         </property>
   55.         <!-- 下面定义BeanNameAutoProxyCreator所需的事务拦截器  -->
   56.         <property name="interceptorNames">
   57.             <list>
   58.                 <!-- 此处可增加其他新的Interceptor -->
   59.                 <value>transactionInterceptor</value>
   60.             </list>
   61.         </property>
   62.     </bean>
   68.     <bean id="AlcorTCountriesDAO" class="com.firemax.test.hibernate.AlcorTCountriesDAO">
   69.         <property name="entityManagerFactory" ref="entityManagerFactory" />
   70.     </bean>
   71.     <bean id="AlcorTProvincesDAO" class="com.firemax.test.hibernate.AlcorTProvincesDAO">
   72.         <property name="entityManagerFactory" ref="entityManagerFactory" />
   73.     </bean>
   74.     <bean id="AlcotTDistrictDAO" class="com.firemax.test.hibernate.AlcotTDistrictDAO">
   75.         <property name="entityManagerFactory" ref="entityManagerFactory" />
   76.     </bean>
   77.     <bean id="AlcorTCitysDAO" class="com.firemax.test.hibernate.AlcorTCitysDAO">
   78.         <property name="entityManagerFactory" ref="entityManagerFactory" />
   79.     </bean>
   81.     <bean id="CountryService" class="com.firemax.test.service.CountryService">
   82.         <property name="alcorTCountriesDAO" ref="AlcorTCountriesDAO" />
   83.         <property name="alcorTProvincesDAO" ref="AlcorTProvincesDAO" />
   84.         <property name="alcorTCitysDAO" ref="AlcorTCitysDAO" />
   85.         <property name="alcotTDistrictDAO" ref="AlcotTDistrictDAO" />
   86.     </bean>
   88. </beans>

    

    

   注意红色部分。这部分和（一）里面提到的那个applicationContext.xml中使用的bean是不同的。这里面已经用到了spring 的jpa部分。

   其中 <property name="persistenceUnitName" value="testerPU" />  是指向了一个 jpa的PU（Persistent Units）

    

   那么这个 是在哪里定义的呢？

   这里的定义是在你的 classes（src）目录下META-INF下的persistence.xml文件中来定义

   persistence.xml文件内容如下：

    

   1. <?xml version="1.0" encoding="UTF-8"?>
   2. <persistence xmlns="http://java.sun.com/xml/ns/persistence"
   3.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   4.     xsi:schemaLocation="http://java.sun.com/xml/ns/persistence
   5.     http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
   6.     version="1.0">
   8.     <persistence-unit name="testerPU"
   9.         transaction-type="RESOURCE_LOCAL">
   10.         <provider>org.hibernate.ejb.HibernatePersistence</provider>
   11.         <class>com.firemax.test.hibernate.AlcorTCountries</class>
   12.         <class>com.firemax.test.hibernate.AlcorTProvinces</class>
   13.         <class>com.firemax.test.hibernate.AlcotTDistrict</class>
   14.         <class>com.firemax.test.hibernate.AlcorTCitys</class>
   15.         <properties>
   16.             <property name="hibernate.connection.driver_class"
   17.                 value="com.mysql.jdbc.Driver" />
   18.             <property name="hibernate.connection.url"
   19.                 value="jdbc:mysql://localhost:3306/alcorweb?useUnicode=true&characterEncoding=utf-8" />
   20.             <property name="hibernate.connection.username"
   21.                 value="alcorweb" />
   22.             <property name="hibernate.connection.password"
   23.                 value="alcorweb" />
   24.             <property name="hibernate.connection.provider_class" value="org.hibernate.connection.C3P0ConnectionProvider"/>
   25.             <property name="hibernate.c3p0.max_size" value="100"/>
   26.             <property name="hibernate.c3p0.min_size"  value="20"/>
   27.             <property name="hibernate.c3p0.timeout"   value="120"/>
   28.             <property name="hibernate.c3p0.max_statements" value="0"/>
   29.             <property name="hibernate.c3p0.idle_test_period"  value="120"/>
   30.             <property name="hibernate.c3p0.acquire_increment" value="5  "/>
   32.             <property name="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider"/>
   33.             <property name="hibernate.cache.use_query_cache" value="false"/>
   34.             <property name="hibernate.show_sql" value="false"/>
   35.             <property name="hibernate.useUnicode" value="true"/>
   36.             <property name="hibernate.characterEncoding" value="utf8"/>
   37.         </properties>
   38.     </persistence-unit>
   39. </persistence>

   仔细观察他的代码，我们发现其实和hibernate.cfg.xml和相似。都有指向pojo的定义 和 database连接的定义。先别着急。我们这次的优化，就先完成这个目标。主要是引入的spring的jpa框架。

   后面将介绍更进一步的优化。来展示jpa 和 注释注入的能力。