2.工厂BeanFactory类,读取工厂配置文件的数据,创建Dao对象,Manager对象

package com.bjpowernode.drp.util;

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

/**
* 抽象工厂,主要创建两个系列的产品：
*   1、Manager系列
*   2、Dao系列产品
* @author Administrator
*
*/
public class BeanFactory {

private static BeanFactory instance = new BeanFactory();

private final String beansConfigFile = "beans-config.xml";

//保存Service相关对象
private Map serviceMap = new HashMap();

//保存Dao相关对象
private Map daoMap = new HashMap();

private Document doc;

private BeanFactory() {
try {
doc = new SAXReader().read(Thread.currentThread().getContextClassLoader().getResourceAsStream(beansConfigFile));
} catch (DocumentException e) {
e.printStackTrace();
throw new RuntimeException();
}
}

public static BeanFactory getInstance() {
return instance;
}

/**
* 根据产品编号取得Service系列产品
* @param beanId
* @return
*/
public synchronized Object getServiceObject(Class c){
//如果存在相关对象实例，返回
if (serviceMap.containsKey(c.getName())) {
return serviceMap.get(c.getName());
}
Element beanElt = (Element)doc.selectSingleNode("//service[@id=\"" + c.getName() + "\"]");
String className = beanElt.attributeValue("class");
Object service = null;
try {
service = Class.forName(className).newInstance();

//将创建好多的对象放到Map中
serviceMap.put(c.getName(), service);
} catch (Exception e) {
throw new RuntimeException();
}
return service;
}

/**
* 根据产品编号取得Service系列产品
* @param beanId
* @return
*/
public synchronized Object getDaoObject(Class c){
//如果存在相关对象实例，返回
if (daoMap.containsKey(c.getName())) {
return daoMap.get(c.getName());
}
Element beanElt = (Element)doc.selectSingleNode("//dao[@id=\"" + c.getName() + "\"]");
String className = beanElt.attributeValue("class");
Object dao = null;
try {
dao = Class.forName(className).newInstance();

//将创建好多的对象放到Map中
daoMap.put(c.getName(), dao);
} catch (Exception e) {
throw new RuntimeException();
}
return dao;
}

public static void main(String[] args) {
//ItemManager itemManager = (ItemManager)BeanFactory.getInstance().getServiceObject("itemManager");
//System.out.println(itemManager);
//ItemDao itemDao = (ItemDao)BeanFactory.getInstance().getDaoObject("com.bjpowernode.drp.basedata.dao.ItemDao");
ItemDao itemDao = (ItemDao)BeanFactory.getInstance().getDaoObject(ItemDao.class);
System.out.println(itemDao);
}
}