解析手撕Spring IOC/DI

 #web.xml

    
 <?xml version="1.0" encoding="UTF-8"?>
    
 <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    
      xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:javaee="http://java.sun.com/xml/ns/javaee"
    
      xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    
      xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/