Factory

package com.sun.spring;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.jdom.Document;
import org.jdom.Element;
import org.jdom.JDOMException;
import org.jdom.input.SAXBuilder;
import org.jdom.xpath.XPath;


public class BeanFactory {
    Map<String, Object> map = new HashMap<String, Object>();
    public void classPathXmlApplicationContext(String str) throws JDOMException, IOException{
        SAXBuilder sb=new SAXBuilder(); 
        Document doc=sb.build(this.getClass().getClassLoader().getResourceAsStream(str)); //构造文档对象
        Element root=doc.getRootElement(); //获取根元素
        List<Element> list=XPath.selectNodes(root, "/beans/bean");//取名字为bean的所有元素 
        for(int i=0;i<list.size();i++){
            Element bean = list.get(i);
            String id = bean.getAttributeValue("id");//这个地方的参数一定不要写错，否则id值就会为null，让我好找了一段时间
            String clazz = bean.getAttributeValue("class");
            Object o = null;
            try {
                o = Class.forName(clazz).newInstance();
            } catch (InstantiationException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IllegalAccessException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (ClassNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            map.put(id, o);
        }
    }
    public Object getBean(String key){
        return map.get(key);
    }
}


----------
package com.sun.spring;
import static org.junit.Assert.*;

import java.io.IOException;

import org.jdom.JDOMException;
import org.junit.Test;


public class BeanFactoryTest {

    @Test
    public void testClassPathXmlApplicationContext() throws JDOMException, IOException {
        BeanFactory f = new BeanFactory();
        f.classPathXmlApplicationContext("com/sun/spring/applicationContext.xml");
        Car c=(Car) (f.getBean("c"));
        c.run();
    }

    @Test
    public void testGetBean() {
        fail("Not yet implemented");
    }

}


----------
package com.sun.spring;

public class Car {
    public void run(){
        System.out.println("汽车.........");
    }
}


----------
<?xml version="1.0" encoding="UTF-8"?>
<!-- 这个bens里不要写命名空间，schemaLocaltion等否则无法正确读取xml文件。具体原因不详 -->
<beans>
 
    <bean id="c" class="com.sun.spring.Car" ></bean>
</beans>