1、首先定义UserModel测试类
package com.gooagoo.ioc; public class UserModel { private String username; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public void printUser(){ System.out.println("User[username=" + this.username + "]"); } } 2、定义applicationContext.xml <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:dubbo="http://code.alibabatech.com/schema/dubbo" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"> <bean id="user" class="com.gooagoo.ioc.UserModel"> <property name="username" value="liup" /> </bean> </beans>3、使用dom4j解析xml文件，并使用反射技术动态创建实例对象，调用setter方法注入属性值
package com.gooagoo.ioc; import java.io.InputStream; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.HashMap; import java.util.List; import java.util.Map; import java.util.Set; import org.dom4j.Document; import org.dom4j.DocumentException; import org.dom4j.Element; import org.dom4j.io.SAXReader; import com.gooagoo.common.utils.FileUtils; public class TestIOC { public static void main(String[] args) throws DocumentException, ClassNotFoundException, InstantiationException, IllegalAccessException, IllegalArgumentException, InvocationTargetException { // 查找配置文件方式: InputStream inputStream = TestIOC.class.getResourceAsStream("/applicationContext.xml"); // 查找原理？ SAXReader saxReader = new SAXReader(); Document xmlDoc = saxReader.read(inputStream); Element rootElement = xmlDoc.getRootElement(); // 示例：Map<beanId,beanInstance> Map<String,Object> beanMap = new HashMap<String,Object>(); String beanId = null; String beanClassName = null; List<Element> subElesFirstLevel = rootElement.elements("bean"); for(Element subEleFirstLevel:subElesFirstLevel){ beanId = subEleFirstLevel.attribute("id").getValue(); beanClassName = subEleFirstLevel.attribute("class").getValue(); // 暂时只处理User if(!beanId.equals("user")){ continue; } Map<String,String> properties = new HashMap<String,String>(); List<Element> subElesSecondLevel = subEleFirstLevel.elements("property"); for(Element subEleSecondLevel:subElesSecondLevel){ properties.put(subEleSecondLevel.attribute("name").getValue(), subEleSecondLevel.attribute("value").getValue()); } // 动态创建类 Class<?> beanClass = Class.forName(beanClassName); // 并没有创建instance，只是将类型描述信息(Class)加载到JVM内存中 // 创建实例并加入Map集合中 Object instanceObj = Class.forName(beanClassName).newInstance(); // 真正实例化 beanMap.put(beanId, instanceObj); // 获取setter方法 Method[] methods = beanClass.getMethods(); // 遍历xml中配置属性集合Map Set<String> keySet = properties.keySet(); for(String key:keySet){ // 遍历找到属性对应setter方法 for(Method method: methods){ if(method.getName().toLowerCase().contains("set") && method.getName().toLowerCase().contains(key)){ // 匹配到setter方法，调用一下将配置的属性值注入 method.invoke(instanceObj, properties.get(key)); } } } } // 测试：根据BeanId获取对应Bean Instance UserModel userTest = (UserModel)beanMap.get("user"); userTest.printUser(); } }