what's the mechanism of xml in spring during the lifecycle of a program?

[aboaabd]

When I need to use Property Place Holder, I just define a bean in spring_config.xml as follows, without doing anything to this bean in java code, how could the spring know that?\[code\] <bean id="configBean" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer" p:location="spring_test/spring.properties"></bean> \[/code\]another confused part is alike: I define two beans in spring_config.xml, namely SqlSessionFactoryBean and MapperFactoryBean, how could spring implement that the MapperFactoryBean acts just like a proxy to my DAO without I having to write any java code?Is there any article on the mechanism of xml parsing or something related? Thanks a lot!