尚学堂_Spring_0100_模拟Spring

尚学堂_Spring2.5_01_模拟Spring

 

      通过模拟Spring，读取Spring的配置文件，理解Spring的IOC/DI功能。

 

      关键类：ClassPathXmlApplicationContext.java

     package com.bjsxt.spring;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;

public class ClassPathXmlApplicationContext implements BeanFactory{
 private Map<String, Object> beans=new HashMap<String, Object>();

 public ClassPathXmlApplicationContext() throws Exception {
  SAXBuilder sb=new SAXBuilder();
    
     Document doc=sb.build(this.getClass().getClassLoader().getResourceAsStream("beans.xml")); //构造文档对象
     Element root=doc.getRootElement(); //获取根元素HD
     List list=root.getChildren("bean");//取名字为disk的所有元素
     for(int i=0;i<list.size();i++){
        Element element=(Element)list.get(i);
        String id=element.getAttributeValue("id");
        String clazz=element.getAttributeValue("class");
        Object o = Class.forName(clazz).newInstance();
        System.out.println(id);
        System.out.println(clazz);
        beans.put(id, o);
       
        for(Element propertyElement : (List<Element>)element.getChildren("property")) {
         String name = propertyElement.getAttributeValue("name"); //userDAO
         String bean = propertyElement.getAttributeValue("bean"); //u
         Object beanObject = beans.get(bean);//UserDAOImpl instance
        
         String methodName = "set" + name.substring(0, 1).toUpperCase() + name.substring(1);
         System.out.println("method name = " + methodName);
        
         Method m = o.getClass().getMethod(methodName, beanObject.getClass().getInterfaces()[0]);
         m.invoke(o, beanObject);
        }
       
       
     } 
  
 }

 
 public Object getBean(String id) {
  return beans.get(id);
 }
 
}

 

 

 

 

 

 

                                    @modaokeng.yongtai.baiyunqu.guangzhou   2014-10-10 2:03