简单模拟Spring管理Bean对象

package cn.Junit.test;

import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.XPath;
import org.dom4j.io.SAXReader;
import org.springframework.beans.factory.config.BeanDefinition;

public class MyClassPathXmlApplicationContext {
private String filemame;
private List<DefBean> list = new ArrayList<DefBean>();
private Map<String, Object> singletons = new HashMap<String, Object>();

public MyClassPathXmlApplicationContext() {
super();
// TODO Auto-generated constructor stub
}

public MyClassPathXmlApplicationContext(String filemame) {
//1. 读取XML配置文件
this.readXML(filemame);
//2.实例化对象
this.instanceBean();
}

private void instanceBean() {
for (DefBean bean : list) {
try {
singletons.put(bean.getId(), Class.forName(bean.getClassName()).newInstance());
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}

private void readXML(String filemame) {
SAXReader saxReader = new SAXReader();
Document document = null;
try {
URL xmlpath = this.getClass().getClassLoader()
.getResource(filemame);
document = saxReader.read(xmlpath);

Map<String, String> nsMap = new HashMap<String, String>();
nsMap.put("ns", "http://www.springframework.org/schema/beans");// 加入命名空间
XPath xsub = document.createXPath("//ns:beans/ns:bean");// 创建beans/bean查询路径
xsub.setNamespaceURIs(nsMap);// 设置命名空间
List<Element> beans = xsub.selectNodes(document);// 获取文档下所有bean节点
for (Element element : beans) {
String id = element.attributeValue("id");// 获取id属性值
String clazz = element.attributeValue("class"); // 获取class属性值
DefBean bean = new DefBean(id, clazz);
list.add(bean);
}
} catch (Exception e) {
e.printStackTrace();
}
}
//3. 获得bean对象
public Object getBean(String key) {
return singletons.get(key);
}

}