自己对spring ioc的理解
此时心情：有时候工作的很努力，很认真也会被辞退，被小外包公司请辞，当然也是一个重新认识自己，提高自己的机会
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我对spring ioc的理解是，1解析xml2利用反射生成类3利用反射构建类之间注入关系
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1.解析xml
<?xml version="1.0" encoding="UTF-8"?><beans><bean id="room" ref="person" /></bean><bean id="person" name="code">package com.howto.parseXML.util;import java.io.File;import java.io.InputStream;import java.util.ArrayList;import java.util.HashMap;import java.util.Iterator;import java.util.List;import java.util.Map;import org.apache.log4j.Logger;import org.dom4j.Document;import org.dom4j.DocumentException;import org.dom4j.Element;import org.dom4j.io.SAXReader;public class ParseXML {static Logger logger = Logger.getLogger(ParseXML.class.getName());public Map<String, Map<String, Object>> parseIOC(String filename) {List parseList = new ArrayList();SAXReader saxReader = new SAXReader();Document document;Map<String, Map<String, Object>> iocMap = new HashMap<String, Map<String, Object>>();try{InputStream input = this.getClass().getClassLoader().getResourceAsStream(filename); document = saxReader.read(input);//document = saxReader.read(new File(filename));Element root_EL = document.getRootElement();for(Iterator iter=root_EL.elementIterator();iter.hasNext();) {Element bean_EL = (Element)iter.next();Map<String, Object> tempMap = new HashMap<String, Object>();tempMap.put("id", bean_EL.attribute("id").getValue());tempMap.put("class", bean_EL.attribute("class").getValue());List<Map<String, String>> propertyList = new ArrayList<Map<String, String>>();for(Iterator iter0=bean_EL.elementIterator();iter0.hasNext();){Element property_EL = (Element)iter0.next();Map<String, String> propertyMap = new HashMap<String, String>();propertyMap.put("name", property_EL.attribute("name").getValue());propertyMap.put("ref", property_EL.attribute("ref").getValue());propertyList.add(propertyMap);}tempMap.put("property", propertyList);iocMap.put(bean_EL.attribute("id").getValue(), tempMap);}} catch(DocumentException e) {e.printStackTrace();}return iocMap;}}?2and3反射生成类并存入map中，构建注入关系
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package com.howto.ioc;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import java.util.Set;import com.howto.parseXML.util.ParseXML;public class BeanFactory {public static Map<String, Object> beanContainer = new HashMap<String, Object>();public static void init() {//通过 反射 初始化 bean instanceBean();//构建 bean 依赖关系 invokeBean();System.out.println("init success!");}publicstatic ParseXML parseXML = new ParseXML();//解析 xmlpublicstatic Map<String, Map<String, Object>> beanXML = parseXML.parseIOC("application.xml");private static void instanceBean() {Set<String> beanKeys = beanXML.keySet();//初始化 beanfor(String beanID: beanKeys) {Map<String, Object> beanDesc = beanXML.get(beanID);Object bean = getBean(beanID);beanContainer.put(beanID, bean);}}private static void invokeBean() {Set<String> beanKeys = beanXML.keySet();for(String beanID: beanKeys) {Map<String, Object> beanDesc = beanXML.get(beanID);invoke(beanDesc);}}private static void invoke(Map<String, Object> beanDesc) {Class<?> beanClass;try {beanClass = Class.forName((String)beanDesc.get("class"));List<Map<String, Object>> methodList = getBeanSetMethod(beanClass, (List<Map<String, String>>)beanDesc.get("property"));for(Map<String, Object> tempMap: methodList) {Method setMethod = (Method)tempMap.get("method");Class<?>[] para = (Class<?>[])tempMap.get("para");String beanID = (String)beanDesc.get("id");Object obj = getBean(beanID);setMethod.invoke(obj, tempMap.get("ref"));System.out.println(obj);}} catch (ClassNotFoundException e) {e.printStackTrace();} catch (IllegalArgumentException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();} catch (InvocationTargetException e) {e.printStackTrace();} }private static List<Map<String, Object>> getBeanSetMethod(Class<?> beanClass, List<Map<String, String>> propertylist) {List<Map<String, Object>> setMethodList = new ArrayList<Map<String, Object>>();for(Map<String, String> propertyMap: propertylist) {Map<String, Object> tempMap = new HashMap<String, Object>();Method setProMethod = getSetMethod(beanClass, propertyMap);Class<?> para[] = setProMethod.getParameterTypes();tempMap.put("methodName", setProMethod.getName());tempMap.put("para", para);tempMap.put("method", setProMethod);tempMap.put("ref", getBean(propertyMap.get("ref")));setMethodList.add(tempMap);}return setMethodList;}//拿到 属性set 方法methodprivate static Method getSetMethod(Class<?> beanClass,Map<String, String> propertyMap) {Method[] methods = beanClass.getMethods();for(Method tempMethod: methods) {if(tempMethod.getName().equals(getSetPramMethodName(propertyMap)))return tempMethod;}return null;}//生成 属性 set 方法名private static Object getSetPramMethodName(Map<String, String> propertyMap) {String prameterName = propertyMap.get("name");String setPramMethodName = "set" + prameterName.substring(0, 1).toUpperCase() + prameterName.substring(1);return setPramMethodName;}private static Object getBean(String beanID) {if(beanContainer.containsKey(beanID)) {return beanContainer.get(beanID);} else {Map<String, Object> beanDesc = beanXML.get(beanID);Object obj = null;try {obj = Class.forName((String)beanDesc.get("class")).newInstance();} catch (InstantiationException e) {e.printStackTrace();} catch (IllegalAccessException e) {e.printStackTrace();} catch (ClassNotFoundException e) {e.printStackTrace();}return obj;}}}?4将其加入到web中，通过servletcontextlistener
package com.howto.ioc;import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;public class IocServletContextListener implements ServletContextListener {@Overridepublic void contextDestroyed(ServletContextEvent arg0) {}@Overridepublic void contextInitialized(ServletContextEvent arg0) {BeanFactory.init();}}<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"id="WebApp_ID" version="2.5"><display-name>ioc_v0.1</display-name><listener><listener-class>com.howto.ioc.IocServletContextListener</listener-class></listener></web-app>
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注：其中model类
package com.howto.parseXML.model;public class Room {public String roomName;public Person person;public String getRoomName() {return roomName;}public void setRoomName(String roomName) {this.roomName = roomName;}public Person getPerson() {return person;}public void setPerson(Person person) {this.person = person;}}?
package com.howto.parseXML.model;public class Person {public String personName;public String age;public String getAge() {return age;}public void setAge(String age) {this.age = age;}public String getPersonName() {return personName;}public void setPersonName(String personName) {this.personName = personName;}}?
之前一直认为ioc很神秘，当真正去了解它的时候，才发现，其思想并不复杂，只是spring 源码过于庞大了，无从下手，以菜鸟的心面的世界，不管我写什么，都是在自己的世界重复发明轮子而已。