1：spring-core
1.1: Definition and loading of resources
The defined interface of the resource is org.springframework.core.io.Resource. The resource loading interface org.springframework.core.io.ResourceLoader. For details, please refer to here .
1.2: Tools
As org.springframework.util.StringUtils.
2：spring-beans
2.1: Document Loader
Load the resource as a document object to prepare for the BeanDefinition obtained by parsing. The interface is org.springframework.beans.factory.xml.DocumentLoader. For details, please refer to here .
2.2: xml bean definition reader
Responsible for reading information from the xml file to generate the BeanDefinition data structure, the top-level interface is org.springframework.beans.factory.support.BeanDefinitionReader, and the implementation class responsible for xml reading is org.springframework.beans.factory.xml.XmlBeanDefinitionReader. For details, please refer to here .