fatory的模拟

最新推荐文章于 2024-06-09 12:58:15 发布

wenwenhappy

最新推荐文章于 2024-06-09 12:58:15 发布

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分类专栏： java web xml

本文链接：https://blog.csdn.net/wenwenhappy/article/details/8977920

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package com.wenwen.drp.beanfactory;

import java.util.HashMap;
import java.util.Map;

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

import org.dom4j.io.SAXReader;

import com.wenwen.drp.basedata.dao.ItemDao;
import com.wenwen.drp.basedata.manager.ItemManager;

public class BeanFactory {
/*
 *装下所用的dao对象
 * */ 
private Map daoMap = new HashMap();
 /*
  * 装下所有的service对象
  * */
 private Map serviceMap = new HashMap();
 private static BeanFactory factory = new BeanFactory();	
 private final String config_file="bean_config.xml";
 private Document doc;
 /*
  * 初始化时将bean_config.xml读取到内存当中
  * */
public BeanFactory(){
	SAXReader reader=new SAXReader();
	try {
		doc = reader.read(Thread.currentThread().getContextClassLoader()
				.getResourceAsStream(config_file));
	} catch (DocumentException e) {
		e.printStackTrace();
	}
}
/*
 * 单例化创建工厂
 * */
public static BeanFactory newInstanse(){
	return factory;
}
/*
 * 拿到dao的完全路径，反射机制创建对象
 * */
///Element beanElt = (Element)doc.selectSingleNode("//service[@id=\"" + serviceId + "\"]");
public Object getInstanceDao(String daoId){
	Object dao = null;
	//若daoMap中存在daoId,说明已经有了这个dao,则直接返回这个daoMap即可
	if(daoMap.containsKey("daoId"))
		return daoMap;
	Element elt = (Element) doc.selectSingleNode("//dao[@id=\""+daoId+"\"]");
	String className = elt.attributeValue("class");
	try {
		dao=Class.forName(className).newInstance();
		daoMap.put(daoId, dao);
	} catch (Exception e) {
		e.printStackTrace();
	}
	//将创建好多的对象放到Map中
	return dao;
}
/*
 * 创建mservice
 * */
public Object getInstanceService(String serviceId){
	Object service = null;
	//若serviceMap中存在serviceId,说明已经有了这个service,则直接返回这个serviceMap即可
	if(serviceMap.containsKey("serviceId"))
		return serviceMap;
	Element elt = (Element) doc.selectSingleNode("//service[@id=\""+serviceId+"\"]");
	String className = elt.attributeValue("class");
	try {
		service=Class.forName(className).newInstance();
		serviceMap.put(serviceId, service);
	} catch (Exception e) {
		e.printStackTrace();
	}
	//将创建好多的对象放到Map中
	return service;
}
public static void main(String[] args){
	ItemDao itemdao = (ItemDao) factory.newInstanse().getInstanceDao("itemdao");
	System.out.println(itemdao);
	ItemManager manager = (ItemManager) factory.newInstanse().getInstanceService("itemManager");
	System.out.println(manager);
}
}

<?xml version="1.0" encoding="UTF-8"?>
<bean>
<dao id="itemdao" class="com.wenwen.drp.basedata.dao.Dao4OracleImpl"/>
<service id="itemManager" class="com.wenwen.drp.basedata.manager.ItemManager"/>
</bean>