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">
   6.     <bean id="entityManagerFactory"
   7.         class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
   8.         <property name="persistenceUnitName" value="testerPU" />
   9.     </bean>
   10.     <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
   11.         <property name="entityManagerFactory" ref="entityManagerFactory" />
   12.     </bean>
   13.     <tx:annotation-driven transaction-manager="transactionManager" />
   14.     <bean id="transactionInterceptor"
   15.         class="org.springframework.transaction.interceptor.TransactionInterceptor">
   16.         <!-- 事务拦截器bean需要依赖注入一个事务管理器 -->
   17.         <property name="transactionManager">
   18.             <ref local="transactionManager" />
   19.         </property>
   20.         <property name="transactionAttributes">
   21.             <!-- 下面定义事务（指service里面的方法）传播属性 -->
   22.             <props>
   23.                 <prop key="insert*">PROPAGATION_REQUIRED</prop>
   24.                 <prop key="update*">PROPAGATION_REQUIRED</prop>
   25.                 <prop key="save*">PROPAGATION_REQUIRED</prop>
   26.                 <prop key="add*">PROPAGATION_REQUIRED</prop>
   27.                 <prop key="update*">PROPAGATION_REQUIRED</prop>
   28.                 <prop key="remove*">PROPAGATION_REQUIRED</prop>
   29.                 <prop key="delete*">PROPAGATION_REQUIRED</prop>
   30.                 <prop key="get*">PROPAGATION_REQUIRED,readOnly
   31.                 </prop>
   32.                 <prop key="find*">PROPAGATION_REQUIRED,readOnly
   33.                 </prop>
   34.                 <prop key="load*">PROPAGATION_REQUIRED,readOnly
   35.                 </prop>
   36.                 <prop key="change*">PROPAGATION_REQUIRED</prop>
   37.                 <prop key="count*">PROPAGATION_REQUIRED</prop>
   38.                 <prop key="*">PROPAGATION_REQUIRED</prop>
   39.             </props>
   40.         </property>
   41.     </bean>
   42.     <!-- 定义自动代理BeanNameAutoProxyCreator -->
   43.     <bean id="beanNameAutoProxyCreator"
   44.         class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
   45.         <!-- 指定对满足哪些bean name的bean自动生成业务代理 -->
   46.         <property name="beanNames">
   47.             <list>
   48.                 <value>*Service</value>
   49.             </list>
   50.         </property>
   51.         <!-- 下面定义BeanNameAutoProxyCreator所需的事务拦截器  -->
   52.         <property name="interceptorNames">
   53.             <list>
   54.                 <!-- 此处可增加其他新的Interceptor -->
   55.                 <value>transactionInterceptor</value>
   56.             </list>
   57.         </property>
   58.     </bean>
   59.     <bean id="AlcorTCountriesDAO" class="com.firemax.test.hibernate.AlcorTCountriesDAO">
   60.         <property name="entityManagerFactory" ref="entityManagerFactory" />
   61.     </bean>
   62.     <bean id="AlcorTProvincesDAO" class="com.firemax.test.hibernate.AlcorTProvincesDAO">
   63.         <property name="entityManagerFactory" ref="entityManagerFactory" />
   64.     </bean>
   65.     <bean id="AlcotTDistrictDAO" class="com.firemax.test.hibernate.AlcotTDistrictDAO">
   66.         <property name="entityManagerFactory" ref="entityManagerFactory" />
   67.     </bean>
   68.     <bean id="AlcorTCitysDAO" class="com.firemax.test.hibernate.AlcorTCitysDAO">
   69.         <property name="entityManagerFactory" ref="entityManagerFactory" />
   70.     </bean>
   71.     <bean id="CountryService" class="com.firemax.test.service.CountryService">
   72.         <property name="alcorTCountriesDAO" ref="AlcorTCountriesDAO" />
   73.         <property name="alcorTProvincesDAO" ref="AlcorTProvincesDAO" />
   74.         <property name="alcorTCitysDAO" ref="AlcorTCitysDAO" />
   75.         <property name="alcotTDistrictDAO" ref="AlcotTDistrictDAO" />
   76.     </bean>
   77. </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">
   7.     <persistence-unit name="testerPU"
   8.         transaction-type="RESOURCE_LOCAL">
   9.         <provider>org.hibernate.ejb.HibernatePersistence</provider>
   10.         <class>com.firemax.test.hibernate.AlcorTCountries</class>
   11.         <class>com.firemax.test.hibernate.AlcorTProvinces</class>
   12.         <class>com.firemax.test.hibernate.AlcotTDistrict</class>
   13.         <class>com.firemax.test.hibernate.AlcorTCitys</class>
   14.         <properties>
   15.             <property name="hibernate.connection.driver_class"
   16.                 value="com.mysql.jdbc.Driver" />
   17.             <property name="hibernate.connection.url"
   18.                 value="jdbc:mysql://localhost:3306/alcorweb?useUnicode=true&characterEncoding=utf-8" />
   19.             <property name="hibernate.connection.username"
   20.                 value="alcorweb" />
   21.             <property name="hibernate.connection.password"
   22.                 value="alcorweb" />
   23.             <property name="hibernate.connection.provider_class" value="org.hibernate.connection.C3P0ConnectionProvider"/>
   24.             <property name="hibernate.c3p0.max_size" value="100"/>
   25.             <property name="hibernate.c3p0.min_size"  value="20"/>
   26.             <property name="hibernate.c3p0.timeout"   value="120"/>
   27.             <property name="hibernate.c3p0.max_statements" value="0"/>
   28.             <property name="hibernate.c3p0.idle_test_period"  value="120"/>
   29.             <property name="hibernate.c3p0.acquire_increment" value="5  "/>
   30.             <property name="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider"/>
   31.             <property name="hibernate.cache.use_query_cache" value="false"/>
   32.             <property name="hibernate.show_sql" value="false"/>
   33.             <property name="hibernate.useUnicode" value="true"/>
   34.             <property name="hibernate.characterEncoding" value="utf8"/>
   35.         </properties>
   36.     </persistence-unit>
   37. </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。