工程模式 JDom读取xml模拟Sping的Bean工厂

 

JDom lib 下载地址：http://www.jdom.org/downloads/index.html

BeanFactory.xml

<?xml version="1.0" encoding="UTF-8"?>

<Beans>
 <bean id="Car" class="com.rain.Factory.Car">
 </bean>
 <bean id="SuperCar" class="com.rain.Factory.SuperCar">
 </bean>

</Beans>

 

IVehicle 接口

package com.rain.Factory;

public interface IVehicle {

	void run();
}

Car

package com.rain.Factory;

public class Car implements IVehicle {

	@Override
	public void run() {
		System.out.println("小汽车跑跑跑");
	}
	@Override
	public String toString() {
		return "Car";
	}
}

SuperCar

package com.rain.Factory;
public class SuperCar implements IVehicle {

	@Override
	public void run() {
		System.out.println("超级跑车");
	}
}

IBeanFactory

package com.rain.Factory;

public interface IBeanFactory {

	Object getBean(String key);
}

ClassPathXmlApplicationContext

package com.rain.Factory;

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.jdom2.*;
import org.jdom2.input.SAXBuilder;
import org.jdom2.xpath.XPath;

public class ClassPathXmlApplicationContext implements IBeanFactory {

	private Map<String, Object> container=new HashMap<String, Object>();

	public ClassPathXmlApplicationContext(String fileName) throws JDOMException, IOException{
		
		SAXBuilder sb = new SAXBuilder();
		//拿到要读取的文件
		  Document doc = sb.build(this.getClass().getClassLoader().getResource(fileName));
		  Element root = doc.getRootElement();
		  //直接难道要读取节点，而不是像传统那样一层层循环查找到节点在读取
		  List list = XPath.selectNodes(root, "/Beans/bean");
		  for (int i = 0; i < list.size(); i++) { 
			   Element bean_element = (Element) list.get(i);
			   String id = bean_element.getAttributeValue("id");
			   String clazz=bean_element.getAttributeValue("class");
			   
				try {
					
					Object object = Class.forName(clazz).newInstance();
					this.container.put(id, object);
					
				} catch (InstantiationException e) {
					e.printStackTrace();
				} catch (IllegalAccessException e) {
					e.printStackTrace();
				} catch (ClassNotFoundException e) {
					e.printStackTrace();
				}
		  }
	}

	@Override
	public Object getBean(String key) {
		return this.container.get(key);
	}
	
	public static void main(String[] args) throws JDOMException, IOException {
		ClassPathXmlApplicationContext c=new ClassPathXmlApplicationContext("com/rain/Factory/BeanFactory.xml");
		Object o=c.getBean("Car");
		IVehicle vehicle=(IVehicle) o;
		vehicle.run();
	}
}

Factory

 

package com.rain.Factory;

import java.io.IOException;

import org.jdom2.JDOMException;

public class Factory {

	public static void main(String[] args) throws JDOMException, IOException {
		IBeanFactory factory=new ClassPathXmlApplicationContext("com/rain/Factory/BeanFactory.xml");
//		IVehicle vehicel=(IVehicle) factory.getBean("Car");
		IVehicle vehicel=(IVehicle) factory.getBean("SuperCar");
		vehicel.run();
	}

}

 

Xpath 实例代码

Sample.xml

<?xml version="1.0" encoding="UTF-8"?>
<HD>
 <disk name="C">
  <capacity>8G</capacity>
  <directories>200</directories>
  <files>1580</files>
 </disk>
 <disk name="D"> 
  <capacity>10G</capacity>
  <directories>500</directories>
  <files>3000</files> 
 </disk>
</HD>

 

Sample

package com.rain.Factory;

import java.io.IOException;
import java.util.List;

import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.Text;
import org.jdom2.input.SAXBuilder;
import org.jdom2.xpath.XPath;

public class Sample {



	public Sample() throws JDOMException, IOException {
		SAXBuilder sb = new SAXBuilder();
		  Document doc = sb.build(this.getClass().getClassLoader().getResource("com/rain/Factory/Sample.xml"));
		  Element root = doc.getRootElement();
		  List list = XPath.selectNodes(root, "/HD/disk");
		  for (int i = 0; i < list.size(); i++) { 
			   Element disk_element = (Element) list.get(i);
			   String name = disk_element.getAttributeValue("name");
			   String capacity = ( (Text) XPath.selectSingleNode(disk_element, 
			    "//disk[@name='" + name + "']/capacity/text()")).getTextNormalize();
			   String directories = ( (Text) XPath.selectSingleNode(disk_element,  
			    "//disk[@name='" + name + "']/directories/text()")).getTextNormalize();
			   String files = ( (Text) XPath.selectSingleNode(disk_element,  
			    "//disk[@name='" + name + "']/files/text()")).getTextNormalize();
			   System.out.println("磁盘信息:");
			   System.out.println("分区盘符:" + name);
			   System.out.println("分区容量:" + capacity);
			   System.out.println("目录数:" + directories);
			   System.out.println("文件数:" + files);
			   System.out.println("-----------------------------------");
		  }
	}
	public static void main(String[] args) throws JDOMException, IOException {
		
		new Sample();

	}


}