Spring_使用XML配置文件创建对象

秒速五厘米 2022-06-15 03:06 162阅读 0赞

package com.bjsxt.spring;
    
    public interface BeanFactory {
    	public Object getBean(String name);
    }

package com.bjsxt.spring;
    
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    import org.jdom2.Document;
    import org.jdom2.Element;
    import org.jdom2.input.SAXBuilder;
    
    public class ClassPathXmlApplicationContext implements BeanFactory {
    	private Map<String, Object> beans = new HashMap<String, Object>();
    
    	public ClassPathXmlApplicationContext() throws Exception {
    		SAXBuilder sb = new SAXBuilder();
    		Document document = sb.build(ClassPathXmlApplicationContext.class
    				.getClassLoader().getResource("beans.xml"));// 获取文件
    		Element root = document.getRootElement();// 获取根元素
    		List list = root.getChildren();// 获取名字为bean的所有元素(子元素)
    		for (int i = 0; i < list.size(); i++) {
    			Element element = (Element) list.get(i);
    			String id = element.getAttributeValue("id");
    			String clazz = element.getAttributeValue("class");
    			System.out.println(id + ":" + clazz);
    			Object obj = Class.forName(clazz).newInstance();
    			beans.put(id, obj);
    		}
    	}
    
    	@Override
    	public Object getBean(String name) {
    		return beans.get(name);
    	}
    
    }

package com.bjsxt.service;
    
    import org.junit.Test;
    
    import com.bjsxt.dao.UserDao;
    import com.bjsxt.model.User;
    import com.bjsxt.spring.BeanFactory;
    import com.bjsxt.spring.ClassPathXmlApplicationContext;
    
    public class UserServiceTest {
    
    	@Test
    	public void testAdd() throws Exception {
    		BeanFactory factory = new ClassPathXmlApplicationContext();
    
    		UserService service = new UserService();
    		UserDao ud = (UserDao) factory.getBean("u");
    		service.setUd(ud);
    		User user = new User();
    		service.add(user);
    	}
    
    }