读取xml配置文件的方法

package com.bluedot.spring;import java.io.InputStream;import java.util.HashMap;import java.util.Map;import javax.xml.parsers.DocumentBuilder;import javax.xml.parsers.DocumentBuilderFactory;import org.w3c.dom.Document;import org.w3c.dom.Element;import org.w3c.dom.NodeList;import com.bluedot.BeanFactory;//读取xml配置文件的方法public class ClassPathXmlApplicationContext implements BeanFactory {private Map<String,Object> map=new HashMap<String,Object>();public ClassPathXmlApplicationContext() {}public ClassPathXmlApplicationContext(String fileName) {DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();try {DocumentBuilder db=dbf.newDocumentBuilder();InputStream is=Thread.currentThread().getContextClassLoader().getResourceAsStream(fileName);Document doc=db.parse(is);NodeList beans=doc.getElementsByTagName("bean");for(int i=0;i<beans.getLength();i++){Element bean=(Element) beans.item(i);String id=bean.getAttribute("id");String className=bean.getAttribute("class");Object value=Class.forName(className).newInstance();map.put(id, value);}} catch (Exception e) {e.printStackTrace();}}@Overridepublic Object getBean(String beanName) {// TODO Auto-generated method stubreturn map.get(beanName);}}