模拟Spring控制反转、依赖注入（包注解）

package com.spring.test;import java.beans.Introspector;import java.beans.PropertyDescriptor;import java.lang.reflect.Field;import java.lang.reflect.Method;import java.net.URL;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import org.dom4j.Document;import org.dom4j.Element;import org.dom4j.XPath;import org.dom4j.io.SAXReader;public class MySpring {List<BeanDefinition> beanDefines=new ArrayList<BeanDefinition>();Map<String, Object> map=new HashMap<String, Object>();public MySpring(String filename){//读取XML文件,遍历bean,存放到ListreadXML(filename);//遍历bean集合,利用反射实例化bean,存放到MapinstanceBean();//依赖注入injectObject();//注解注入annotationInject();}private void annotationInject() {for(String name : map.keySet()){Object bean=map.get(name);if(bean!=null){try {PropertyDescriptor[] ps=Introspector.getBeanInfo(bean.getClass()).getPropertyDescriptors();for(PropertyDescriptor propertyDescriptor : ps){Method setter=propertyDescriptor.getWriteMethod();//获取setter方法//判断注解是否存在if(setter!=null && setter.isAnnotationPresent(MyResource.class)){MyResource myResource=setter.getAnnotation(MyResource.class);Object value=null;//声明name属性if(myResource.name()!=null && !"".equals(myResource.name())){value=map.get(myResource.name());}else{value=map.get(propertyDescriptor.getName());if(value==null){for(String key : map.keySet()){if(propertyDescriptor.getPropertyType().isAssignableFrom(map.get(key).getClass())){value=map.get(key);break;}}}}setter.setAccessible(true);setter.invoke(bean, value);//把引用对象注入到属性中}}//字段Field[] fields=bean.getClass().getFields();for(Field field : fields){if(field.isAnnotationPresent(MyResource.class)){MyResource myResource=field.getAnnotation(MyResource.class);Object value=null;//声明name属性if(myResource.name()!=null && !"".equals(myResource.name())){value=map.get(myResource.name());}else{value=map.get(field.getName());if(value==null){for(String key : map.keySet()){if(field.getType().isAssignableFrom(map.get(key).getClass())){value=map.get(key);break;}}}}field.setAccessible(true);field.set(bean,value);}}} catch (Exception e) {e.printStackTrace();}}}}private void injectObject() {//循环所有的bean节点for(BeanDefinition beanDefinition : beanDefines){Object bean= map.get(beanDefinition.getId());if(bean!=null){try {PropertyDescriptor[] ps=Introspector.getBeanInfo(bean.getClass()).getPropertyDescriptors();//循环所有的property节点for(PropertyDefinition propertyDefinition : beanDefinition.getProperties()){for(PropertyDescriptor propertyDescriptor : ps){if(propertyDefinition.getName().equals(propertyDescriptor.getName())){Method setter=propertyDescriptor.getWriteMethod();//获取setter方法if(setter!=null){Object value=map.get(propertyDefinition.getRef());//如果private,设置允许访问setter.setAccessible(true);setter.invoke(bean, value);//把引用对象注入到属性中}break;}}}} catch (Exception e) {e.printStackTrace();}}}}@SuppressWarnings("unchecked")private void readXML(String filename) {SAXReader saxReader = new SAXReader();           Document document=null;           try{         URL xmlpath = this.getClass().getClassLoader().getResource(filename);         document = saxReader.read(xmlpath);         Map<String,String> nsMap = new HashMap<String,String>();         nsMap.put("ns","http://www.springframework.org/schema/beans");//加入命名空间         XPath xsub = document.createXPath("//ns:beans/ns:bean");//创建beans/bean查询路径         xsub.setNamespaceURIs(nsMap);//设置命名空间         List<Element> beans = xsub.selectNodes(document);//获取文档下所有bean节点                   for(Element element : beans){            String id = element.attributeValue("id");//获取id属性值            String clazz = element.attributeValue("class"); //获取class属性值                    BeanDefinition beanDefine = new BeanDefinition(id, clazz);                        XPath propertysub = element.createXPath("ns:property");//创建beans/property查询路径            propertysub.setNamespaceURIs(nsMap);//设置命名空间            List<Element> propertys = propertysub.selectNodes(element);//获取文档下所有property节点             for(Element property : propertys){            String propertyName=property.attributeValue("name");            String propertyRef=property.attributeValue("ref");            System.out.println(propertyName+propertyRef);            PropertyDefinition pd=new PropertyDefinition(propertyName,propertyRef);            beanDefine.getProperties().add(pd);            }                        beanDefines.add(beanDefine);         }           }catch(Exception e){               e.printStackTrace();        }}private void instanceBean() {for(BeanDefinition bean : beanDefines){try {if(bean.getClassName()!=null && !"".equals(bean.getClassName()))//实例化Bean对象map.put(bean.getId(), Class.forName(bean.getClassName()).newInstance());} catch (Exception e) {e.printStackTrace();}}}public Object getBean(String id){return this.map.get(id);}}