Spring 外部化bean配置

在配置文件中配置Bean 时，你必须记住，将部署细节如文件路径，服务器地址，用户名称和密码与Bean配置混在一起是不好的做法。通常Bean的配置由开发人员编写，而部署细节因不同的环境而不同，如果开发环境和测试环境以及预发布环境和线上环境等。

     如何解决不同环境不同导致的重复修改Bean配置呢？

      Spring 有 一个名称为PropertyPlaceHolderConfigurer的Bean工厂后处理器，用来将部分Bean配置外部化为一个属性文件。你可以在 Bean的配置文件中使用${var}形式的变量，PropertyPlaceHolderConfigurer会从属性文件中加载属性并替换他们。

   

<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:p="http://www.springframework.org/schema/p" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:jee="http://www.springframework.org/schema/jee"
	xmlns:task="http://www.springframework.org/schema/task"
	xsi:schemaLocation="
		http://www.springframework.org/schema/beans
		http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
		http://www.springframework.org/schema/context
		http://www.springframework.org/schema/context/spring-context-3.0.xsd
		http://www.springframework.org/schema/aop 
		http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
		http://www.springframework.org/schema/tx
		http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
		http://www.springframework.org/schema/jee 
		http://www.springframework.org/schema/jee/spring-jee-3.0.xsd
		http://www.springframework.org/schema/task  
        http://www.springframework.org/schema/task/spring-task-3.1.xsd  
		">
	<context:component-scan base-package="com.david.*" />
	<context:property-placeholder location="config.properties" />
	<!-- <bean class="org.springframework.remoting.rmi.RmiServiceExporter" p:service-ref="spitterService" 
		p:serviceName="SpitterService" p:serviceInterface="com.david.service.SpitterService" 
		/> <bean id="spitterService" class="com.david.service.impl.SpitterServiceImpl" 
		/> -->
	<bean
		class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping" />
	<bean
		class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
		<property name="messageConverters">
			<list>
				<bean
					class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
					<property name="supportedMediaTypes">
						<list>
							<value>text/html;charset=UTF-8</value>
							<value>application/json;charset=UTF-8</value>
						</list>
					</property>
				</bean>
			</list>
		</property>
	</bean>
	<!-- <bean id="spitterServiceRmi" class="org.springframework.remoting.rmi.RmiProxyFactoryBean" 
		p:serviceUrl="rmi://localhost/SpitterService" p:serviceInterface="com.david.service.SpitterService" 
		/> -->
	<!-- 定义数据源 -->
	<bean id="ams" class="com.mchange.v2.c3p0.ComboPooledDataSource"
		destroy-method="close">
		<property name="driverClass" value="${jdbc.ams.driver}" />
		<property name="jdbcUrl" value="${jdbc.ams.url}" />
		<property name="user" value="${jdbc.ams.username}" />
		<property name="password" value="${jdbc.ams.password}" />
		<property name="initialPoolSize" value="${initialSize}" />
		<property name="minPoolSize" value="${minPoolSize}" />
		<property name="maxPoolSize" value="${maxActive}" />
		<property name="acquireIncrement" value="${acquireIncrement}" />
		<property name="maxIdleTime" value="${maxIdleTime}" />
	</bean>

	<!-- 定义jdbc模板类 -->
	<bean id="jdbcTemplate" class="org.springframework.jdbc.core.JdbcTemplate">
		<property name="dataSource" ref="ams" />
	</bean>

	<tx:advice id="txAdvice" transaction-manager="transactionManager">
		<tx:attributes>
			<tx:method name="addBook" propagation="REQUIRED" />
			<tx:method name="deleteBook" propagation="REQUIRES_NEW" />
			<tx:method name="addUser" propagation="NESTED"/>
		</tx:attributes>
	</tx:advice>
	<bean id="transactionManager"
		class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
		<property name="dataSource" ref="ams" />
	</bean>
	<aop:config>
		<aop:advisor
			pointcut="execution(* *..david.service.UserService*.*(..))||execution(* *..david.common.facade.ServiceFacade.*(..))||execution(* *..david.service.BookService.*(..))"
			advice-ref="txAdvice" />
	</aop:config>
</beans>