<?xml version="1.0" encoding="UTF-8" ?>
<!--跟标签beans，里面配置一个又一个的bean子标签，每一个bean子标签都代表一个类的配置-->
<beans>
    <!--id标识对象，class是类的全限定类名-->
    <bean id="orderDao" class="com.customize.spring.dao.impl.OrderDaoImpl">
    </bean>

    <bean id="stockDao" class="com.customize.spring.dao.impl.StockDaoImpl">
    </bean>

    <bean id="orderService" class="com.customize.spring.service.impl.OrderServiceImpl">
        <!--通过set方法注入-->
        <property name="setOrderDao" ref="orderDao"></property>
        <property name="setStockDao" ref="stockDao"></property>
    </bean>
</beans>

public class BeanFactory {

    /**
     * 存放对象
     */
    private static Map<String, Object> map = new ConcurrentHashMap<>();

    /**
     * 对外提供的接口
     * @param id
     * @return
     */
    public static  Object getBean(String id) {
        return map.get(id);
    }

    static {
        // 只加载一次就是在BeanFactory初始化的时候去加载类
        // 任务一：读取解析xml，通过反射技术实例化对象并且存储待用（map集合）
        System.out.println("开始加载Bean对象");
        // 加载xml
        InputStream resourceAsStream = BeanFactory.class.getClassLoader().getResourceAsStream("beans.xml");
        // 解析xml
        SAXReader saxReader = new SAXReader();
        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();
            List<Element> beanList = rootElement.selectNodes("//bean");
            for (int i = 0; i < beanList.size(); i++) {
                Element element = beanList.get(i);
                // 处理每个bean元素，获取到该元素的id 和 class 属性
                String id = element.attributeValue("id");
                String clazz = element.attributeValue("class");
                // 通过反射技术实例化对象
                Class<?> aClass = Class.forName(clazz);
                Object o = aClass.newInstance();
                // 存储到map中待用
                map.put(id,o);
            }
            // 实例化完成之后维护对象的依赖关系，检查哪些对象需要传值进入，根据它的配置，我们传入相应的值
            // 有property子元素的bean就有传值需求
            List<Element> propertyList = rootElement.selectNodes("//property");
            // 解析property，获取父元素
            for (int i = 0; i < propertyList.size(); i++) {
                Element element = propertyList.get(i);
                String name = element.attributeValue("name");
                String ref = element.attributeValue("ref");

                // 找到当前需要被处理依赖关系的bean
                Element parent = element.getParent();
                // 调用父元素对象的反射功能
                String parentId = parent.attributeValue("id");
                Object parentObject = map.get(parentId);
                // 遍历父对象中的所有方法，找到"set" + name
                Method[] methods = parentObject.getClass().getMethods();
                for (int j = 0; j < methods.length; j++) {
                    Method method = methods[j];
                    // 该方法就是 setAccountDao(AccountDao accountDao)
                    if(method.getName().equalsIgnoreCase(name)) {
                        method.invoke(parentObject,map.get(ref));
                    }
                }
                // 把处理之后的parentObject重新放到map中
                map.put(parentId,parentObject);
            }
            System.out.println("加载完毕,Map中的Bean对象个数为:" + map.size());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

public class OrderServiceImpl implements OrderService {

    private OrderDao orderDao;
    private StockDao stockDao;

    public void setOrderDao(OrderDao orderDao) {
        this.orderDao = orderDao;
    }

    public void setStockDao(StockDao stockDao) {
        this.stockDao = stockDao;
    }

    @Override
    public void order(Order order) {
// 没有IOC容器的情况下
// OrderDao orderDao = new OrderDaoImpl();
// // 保存订单
// orderDao.save(order);
//
// //扣除库存
// StockDao stockDao = new StockDaoImpl();
// stockDao.subStock(order.getName());

        // 有IOC容器的基础上
        orderDao.save(order);

        //扣除库存
        stockDao.subStock(order.getName());
        System.out.println("下单成功");
    }
}