spring properties

jingbo2759 的 spring 引用properties文件里的配置(转)
1.PropertyPlaceholderConfigurer类

它是把属性中的定义的变量(var)替代,spring的配置文件中使用${var}的占位符

<beans>

<bean id="configBean" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

           <property name="location"><value>db.properties</value></property>

</bean> 

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

    <property name="driverClassName"><value>${jdbc.driverClassName}</value></property>

    <property name="url"><value>${jdbc.url}</value></property>

    <property name="username"><value>${jdbc.username}</value></property>

    <property name="password"><value>${jdbc.password}</value></property>

</bean>

</beans>

db.properties文件

jdbc.driverClassName=org.hsqldb.jdbcDriver

jdbc.url=jdbc:hsqldb:hsql://production:9002

jdbc.username=sa

jdbc.password=root

2.PropertyOverrideConfigurer类

跟PropertyPlaceholderConfigurer功能一样，不过用法不一样.不用占位符，在属性文件中

直接定义属性的值，这样就允许有默认值

<beans>

<bean id="configBean" class="org.springframework.beans.factory.config.PropertyOverrideConfigurer">

           <property name="location"><value>db.properties</value></property>

</bean> 

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

    <property name="driverClassName"><value>org.hsqldb.jdbcDriver</value></property>

    <property name="url"><value>jdbc:hsqldb:hsql://production:9002</value></property>

    <property name="username"><value>test</value></property>

    <property name="password"><value>123456</value></property>

</bean>

</beans>

db.properties文件

在bean实例时，admin,9527将替代test,123456

3其他

1)如果需要引用多个属性，将configBean属性改为

2)在ApplactionContext中是自动调用BeanFactoryPostProcessor接口的，如果要在BeanFactory中使用，必须手动添加:

dataSource.username=admin

dataSource.password=9527

<property name="locations">

<list>

<value>db.properties</value>

<value>db1.properties</value>

</list>

</property>

XmlBeanFactory factory = new XmlBeanFactory(new FileSystemResource("beans.xml"));

PropertyPlaceholderConfigurer cfg = new PropertyPlaceholderConfigurer();

cfg.setLocation(new FileSystemResource("jdbc.properties"));

cfg.postProcessBeanFactory(factory)