Spring读取xml配置文件的原理与实现

package com.spring.test;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;

public class ApplicationXmlPathContext  implements ApplicationContext{
public static String PATH = null;
public static HashMap<String, Object> hashMap = new HashMap<String,Object>();
public ApplicationXmlPathContext(String xml)
{
//获取文件的地址
PATH = this.getClass().getClassLoader().getResource(xml).getPath();
parsexml(PATH);
}
public void parsexml(String PATH){
try{

SAXReader saxReader = new SAXReader();
Document document = saxReader.read(new File(PATH));
Element ele = document.getRootElement();
//listNodes(ele,null,null);
List<Element> elements = ele.elements();
//将每一个标签保存到集合。用id进行区分
for (Element e :
elements) {
hashMap.put(e.attributeValue("id"),e);
}

}catch (DocumentException e)
{

}
}

public Object getObj(String id) {
Element e = (Element) hashMap.get(id);
String className = e.attributeValue("class");
Class c1 = null;Object obj = null;
try {
c1 = Class.forName(className);
obj = c1.newInstance();//利用反射创建对象
} catch (Exception e1) {
e1.printStackTrace();
}
List<Element> elements = e.elements();
for (Element element :
elements) {
//List attributes = element.attributes();

String elementName = element.attributeValue("name");
String elementValue = element.attributeValue("value");
Method[] methods = c1.getMethods();
for(int j =0;j<methods.length;j++)
{
try {
if(methods[j].getName().indexOf("set")!=-1)
{
if(methods[j].getName().substring(3).toLowerCase().equals(elementName))
{
methods[j].invoke(obj,elementValue);
//调用其配置的set方法，将属性注入对象
}
}

} catch (Exception e1 )
{
e1.printStackTrace();
}
}

}
return obj;
}

public Object getBean(String id) {

return getObj(id);
}
public static void main(String[] args)
{
ApplicationContext ac = new ApplicationXmlPathContext("application.xml");
Student Student = (Student)ac.getBean("Student");
System.out.println(Student.getAdd());

//        String add = studentService.getStudent().getAdd();
//        String name = studentService.getStudent().getAdd();
//
//        System.out.println("i,am="+name+"==add=="+add);
//        System.out.println(PATH);
}
}