java使用dom4j解析xml配置文件实现抽象工厂反射示例

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    <?xml version="1.0" encoding="UTF-8"?>   
    <beans>   
         <service-class>   
            <service id="com.xxjstgb.drp.basedata.manager.ItemManager" class="com.xxjstgb.drp.basedata.manager.ItemManagerImpl" />   
            <service id="com.xxjstgb.drp.flowcard.manager.FlowCardManager" class="com.xxjstgb.drp.flowcard.manager.impl.FlowCardManagerImpl" />   
         </service-class>   
         <dao-class>   
            <dao id="com.xxjstgb.drp.basedata.dao.ItemDao" class="com.xxjstgb.drp.basedata.dao.ItemDao4OracleImpl" />   
            <dao id="com.xxjstgb.drp.flowcard.dao.FlowCardDao" class="com.xxjstgb.drp.flowcard.dao.impl.FlowCardDaoImpl" />   
         </dao-class>   
    </beans>   

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    package com.xxjstgb.drp.util;   

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

    //dom4j   
    import org.dom4j.Document;   
    import org.dom4j.DocumentException;   
    import org.dom4j.Element;   
    import org.dom4j.io.SAXReader;   

    import com.xxjstgb.drp.basedata.dao.ItemDao;   
    import com.xxjstgb.drp.basedata.manager.ItemManager;   
    import com.xxjstgb.drp.flowcard.dao.FlowCardDao;   
    import com.xxjstgb.drp.flowcard.manager.FlowCardManager;   

    /**  
     * 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 liuzhengquan  
     *  
     */   
    public class BeanFactory {   

        private static BeanFactory instance=new BeanFactory();   

        //系统缺省配置文件名称   
        private final String beansConfigFile="beans-config.xml";   

        //保存Dao相关对象   
        private Document doc;   

        /*  
         * key=配置文件中的id值  
         * value=对应了该Id的对象  
         */   
        private Map serviceMap = new HashMap();//保存Service相关对象   
        private Map daoMap = new HashMap();//保存Dao相关对象   

           
        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 serviceId  
         * @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Dao系列产品  
         * @param daoId  
         * @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();   

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

           
        /**  
         * 测试  
         * @param args  
         */   
        public static void main(String[] args){   
            ItemManager itemManager=(ItemManager)BeanFactory.getInstance().getServiceObject(ItemManager.class);   
            System.out.println("itemManager"+itemManager);   

            ItemDao itemDao=(ItemDao)BeanFactory.getInstance().getDaoObject(ItemDao.class);   
            System.out.println("itemDao:"+itemDao);   

            FlowCardManager flowCardManager=(FlowCardManager)BeanFactory.getInstance().getServiceObject(FlowCardManager.class);   
            //FlowCardManager flowCardManager=new FlowCardManagerImpl();   
            System.out.println(flowCardManager);   

            FlowCardDao flowCardDao=(FlowCardDao)BeanFactory.getInstance().getDaoObject(FlowCardDao.class);   
            //FlowCardDao flowCardDao=new FlowCardDaoImpl();   
            System.out.println("flowCardDao:"+flowCardDao);   
        }   

    }