1:遍歷所有的bean物件  得到一個bean物件

2:獲取物件的屬性描述

3:得到屬性的setter方法 並判斷setter方法上面是否有註解

4:取得註解 判斷註解是否有name

5:如果有name的話  就直接把引用物件注入到屬性

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.XPath;
import org.dom4j.io.SAXReader;
public class ClassPathXMLApplicationContext {
	//用來存放bean的資訊
	private List<BeanDefinition> BeanDefines = new ArrayList<BeanDefinition>(); 
	//儲存bean
	private Map<String ,Object > sigletons =new HashMap<String, Object>();

	public  ClassPathXMLApplicationContext(String fileName){
		this.readXML(fileName);//讀XML檔案
		this.instanceBeans();//例項化bean物件
		this.annotationInject();//處理註解的方法
		this.injectObject();//為bean物件的屬性注入值
	}

	//處理註解的方法
	private void annotationInject() {
		// 遍歷所有的bean物件
		for(String beanName:sigletons.keySet()){
			Object  bean = sigletons.get(beanName);
			if(bean!=null ){
				try {
					PropertyDescriptor[] ps = Introspector.getBeanInfo(bean.getClass()).getPropertyDescriptors();
					for(PropertyDescriptor properdesc:ps){
						Method setter = properdesc.getWriteMethod();
						if(setter!=null && setter.isAnnotationPresent(AllenResource.class)){
							AllenResource resource = setter.getAnnotation(AllenResource.class);
							Object value = null;
							if(resource.name()!=null && !"".equals(resource.name())){
								value = sigletons.get(resource.name());
							}else {
								value = sigletons.get(properdesc.getName());
								if(value==null){
									for(String key : sigletons.keySet()){
										if(properdesc.getPropertyType().isAssignableFrom(sigletons.get(key).getClass())){
											value = sigletons.get(key);
											break;
										}
									}
								}
							}
							setter.setAccessible(true);
							setter.invoke(bean, value);
						}
					}
					
					Field[] fields = bean.getClass().getDeclaredFields();
					for(Field field:fields){
						if(field.isAnnotationPresent(AllenResource.class)){
							AllenResource resource = field.getAnnotation(AllenResource.class);
							Object value = null;
							if(resource.name()!=null && !"".equals(resource.name())){
								value = sigletons.get(resource.name());
							}else {
								value = sigletons.get(field.getName());
								if(value==null){
									for(String key : sigletons.keySet()){
										if(field.getType().isAssignableFrom(sigletons.get(key).getClass())){
											value = sigletons.get(key);
											break;
										}
									}
								}
							}
							field.setAccessible(true);
							field.set(bean, value);
						}
					}
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		}
	}
	//為bean物件的屬性注入值
	private void injectObject() {
		for (BeanDefinition beanDefinition :BeanDefines) {
			//例項化過後的bean
			Object bean = sigletons.get(beanDefinition.getId());
			if(bean!=null){
				try {
					PropertyDescriptor[] ps=Introspector.getBeanInfo(bean.getClass()).getPropertyDescriptors();
					for(PropertyDefinition propertyDefinition:beanDefinition.getProperties()){
						for(PropertyDescriptor properdesc:ps){
							if(propertyDefinition.getName().equals(properdesc.getName())){
								Method setter =properdesc.getWriteMethod();//獲取setter方法
								if(setter!=null){
									Object value =null;
									if(propertyDefinition.getRef()!=null && !"".equals(propertyDefinition.getRef())){
										value  =sigletons.get(propertyDefinition.getRef());
										System.out.println(value);
									}else {
										System.out.println(properdesc.getPropertyType());
										value  =propertyDefinition.getValue();
									}
									setter.setAccessible(true);//允許呼叫private的方法
									setter.invoke(bean, value);//把應用物件注入到屬性
								}
							}
						}
					}
				} catch (Exception e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
		}
	}
//完成bean的例項化
	private void instanceBeans() {
		for(BeanDefinition beanDefinition:BeanDefines){
			try {
				if(beanDefinition.getClassName()!=null && !"".equals(beanDefinition.getClassName().trim()))
				sigletons.put(beanDefinition.getId(),Class.forName(beanDefinition.getClassName()).newInstance());
			} catch (Exception e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			} 
		}
	}
	
	//讀取app*.xml裡面的內容
	private void readXML(String fileName) {
		SAXReader  saxReader = new SAXReader();
		Document  document =null;
		try{
			URL xmlPath=this.getClass().getClassLoader().getResource(fileName);
			//System.out.println(xmlPath);file:/G:/workspaces1/spring/bin/beans.xml
			document =saxReader.read(xmlPath);
			Map<String,String> nsMap=new HashMap<String, String>();
			//加入名稱空間
			nsMap.put("ns","http://www.springframework.org/schema/beans");
			//建立beans/bean的查詢路徑
			XPath xsub = document.createXPath("//ns:beans/ns:bean");
			//System.out.println(xsub);[XPath: /descendant-or-self::node()/child::ns:beans/child::ns:bean]
			//設定名稱空間
			xsub.setNamespaceURIs(nsMap);
			//獲取文件下的所有的bean節點
			List<Element>  beans = xsub.selectNodes(document);
			for (Element element : beans) {
				String id =element.attributeValue("id");//獲取id屬性值
				String clazz = element.attributeValue("class");//獲取class屬性值
				BeanDefinition beanDefine =new  BeanDefinition(id, clazz);
				
				//得到bean下面的所有property節點
				XPath propertyPath = document.createXPath("ns:property");
				propertyPath.setNamespaceURIs(nsMap);
				List<Element> properties =propertyPath.selectNodes(element);
				
				for(Element property:properties){
					String  propertyName = property.attributeValue("name");
					String  propertyRef  = property.attributeValue("ref");
					String  propertyValue  = property.attributeValue("value");
					//System.out.println(propertyName+"="+propertyRef+propertyValue);
					PropertyDefinition propertyDefinition =new  PropertyDefinition(propertyName, propertyRef,propertyValue);
					beanDefine.getProperties().add(propertyDefinition);
				}
				
				BeanDefines.add(beanDefine);
			}
		}catch(Exception e){
			e.printStackTrace();
		}
	}
	//獲取bean例項
	public Object getBean(String beanName){
		return this.sigletons.get(beanName);
	}
}
 

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