注解的力量 Spring 2.5 JPA hibernate 使用方法的点滴整理（四）:使用 命名空间 简化配置

 在（三）里面。我们引入了 <bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>这个bean 来处理@Autowired注解。

其实在spring 里面还有其他三个BeanPostProcessor 。总共有四个，分别是：

AutowiredAnnotationBeanPostProcessor

CommonAnnotationBeanPostProcessor

PersistenceAnnotationBeanPostProcessor

equiredAnnotationBeanPostProcessor 

 

但是直接在 Spring 配置文件中定义这些 Bean 显得比较笨拙。Spring 为我们提供了一种方便的注册这些 BeanPostProcessor 的方式，这就是 <context:annotation-config/>

 

Spring 2.1 添加了一个新的 context 的 Schema 命名空间，该命名空间对注释驱动、属性文件引入、加载期织入等功能提供了便捷的配置。我们知道注释本身是不会做任何事情的，它仅提供元数据信息。要使元数据信息真正起作用，必须让负责处理这些元数据的处理器工作起来。

 

这段代码就是 启用了这个命名空间后的applicationContext.xml文件

1. <?xml version="1.0" encoding="UTF-8"?>
2. <beans xmlns="http://www.springframework.org/schema/beans"
3.     xmlns:context="http://www.springframework.org/schema/context"
4.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
5.     xmlns:tx="http://www.springframework.org/schema/tx"
6.     xsi:schemaLocation="http://www.springframework.org/schema/beans   http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
7.                                             http://www.springframework.org/schema/context  http://www.springframework.org/schema/context/spring-context-2.5.xsd
8.                                             http://www.springframework.org/schema/tx  http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"
9.     >
10.     <bean id="entityManagerFactory"
11.         class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean">
12.         <property name="persistenceUnitName" value="testerPU" />
13.     </bean>
14.     <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
15.         <property name="entityManagerFactory" ref="entityManagerFactory" />
16.     </bean>
17.     <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.     
47.     <!-- 该 BeanPostProcessor 将自动对标注 @Autowired 的 Bean 进行注入 -->
48.     <!--  这个Processor 已经被 <context:annotation-config/> 所简化   
49.     <bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>
50.     -->
51.     <context:annotation-config/>
52.     
53.     
54.     <!-- 定义自动代理BeanNameAutoProxyCreator -->
55.     <bean id="beanNameAutoProxyCreator"
56.         class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
57.         <!-- 指定对满足哪些bean name的bean自动生成业务代理 -->
58.         <property name="beanNames">
59.             <list>
60.                 <value>*Service</value>
61.             </list>
62.         </property>
63.         <!-- 下面定义BeanNameAutoProxyCreator所需的事务拦截器  -->
64.         <property name="interceptorNames">
65.             <list>
66.                 <!-- 此处可增加其他新的Interceptor -->
67.                 <value>transactionInterceptor</value>
68.             </list>
69.         </property>
70.     </bean>
71.     <bean id="AlcorTCountriesDAO" class="com.firemax.test.hibernate.AlcorTCountriesDAO">
72.         <property name="entityManagerFactory" ref="entityManagerFactory" />
73.     </bean>
74.     <bean id="AlcorTProvincesDAO" class="com.firemax.test.hibernate.AlcorTProvincesDAO">
75.         <property name="entityManagerFactory" ref="entityManagerFactory" />
76.     </bean>
77.     <bean id="AlcotTDistrictDAO" class="com.firemax.test.hibernate.AlcotTDistrictDAO">
78.         <property name="entityManagerFactory" ref="entityManagerFactory" />
79.     </bean>
80.     <bean id="AlcorTCitysDAO" class="com.firemax.test.hibernate.AlcorTCitysDAO">
81.         <property name="entityManagerFactory" ref="entityManagerFactory" />
82.     </bean>
83.     <bean id="CountryService" class="com.firemax.test.service.CountryService"/>
84. </beans>

注意2段标红的内容，就是这次更新的配置内容。在配置文件中使用 context 命名空间之前，必须在 <beans> 元素中声明 context 命名空间。