xml方式简单实现springIOC

1：什么是IOC IOC是一种思想==控制反转，IOC意味着将你设计好的对象交给容器控制，而不是传统的在你的对象内部直接控制，在springIOC中,就是由spring来负责控制对象的生命周期和对象间的关系。 2 ：IOC实现思路 SpringIOC实现思路有两种， 一种是通过xml+反射, 第二种是通过注解+扫包+反射。 2.1：通过xml实现，先获取xml文件，读取该xml,根据传入的参数匹配对应的beanId，得到class地址，通过反射创建的对象注入容器（ConcurrentHashMap） 2.2：通过注解实现，先获取扫描的路径范围，判断类上是否加上了注解，把加上注解的类通过反射创建出对象注入到容器中（ConcurrentHashMap）注意，key首字母小写。 通过注解实现IOC====》传送门 自己的一点理解，如有不对请过往大神指出，感激！！！ 目录结构: 项目是用maven管理，所使用jar

<!-- 引入Spring-AOP等相关Jar --> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-core</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-aop</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>3.0.6.RELEASE</version> </dependency> <dependency> <groupId>org.aspectj</groupId> <artifactId>aspectjrt</artifactId> <version>1.6.1</version> </dependency> <dependency> <groupId>aspectj</groupId> <artifactId>aspectjweaver</artifactId> <version>1.5.3</version> </dependency> <dependency> <groupId>cglib</groupId> <artifactId>cglib</artifactId> <version>2.1_2</version> </dependency> <!-- https://mvnrepository.com/artifact/com.mchange/c3p0 --> <dependency> <groupId>com.mchange</groupId> <artifactId>c3p0</artifactId> <version>0.9.5.2</version> </dependency> <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.37</version> </dependency> <!-- https://mvnrepository.com/artifact/dom4j/dom4j --> <dependency> <groupId>dom4j</groupId> <artifactId>dom4j</artifactId> <version>1.6.1</version> </dependency> <!-- https://mvnrepository.com/artifact/commons-lang/commons-lang --> <dependency> <groupId>commons-lang</groupId> <artifactId>commons-lang</artifactId> <version>2.6</version> </dependency>

测试用spring.xml

<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:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"> <bean id="userService" class="com.wtk.mvcframework.service.impl.UserServiceImpl"></bean> </beans>

核心类，该类用于创建对象

package com.wtk.mvcframework.xml.spring; import org.apache.commons.lang.StringUtils; import org.dom4j.Document; import org.dom4j.DocumentException; import org.dom4j.Element; import org.dom4j.io.SAXReader; import java.io.InputStream; import java.util.List; public class WTKClassPathXmlApplicationContext { //读取xml地址 private String xmlPath; public WTKClassPathXmlApplicationContext(String xmlPath){ this.xmlPath = xmlPath; } public Object getBean(String beanId) throws Exception { if (StringUtils.isEmpty(beanId)){ throw new Exception("beanid不能为空"); } //解析XML List<Element> readerXml = readerXml(); if (readerXml==null||readerXml.isEmpty()){ throw new Exception("readerXml不能为空"); } //2使用方法参数beanid查找 String calssName= findByElementClass(readerXml,beanId); if(StringUtils.isEmpty(calssName)){ throw new Exception("该bean对象没有配置class地址"); } return newInstance(calssName); //使用反射机制初始化 } //使用方法参数beanid查找配置文件中bean节点的id信息是否一致。 public String findByElementClass(List<Element> readerXml,String beanId){ for (Element element : readerXml){ //获取属性信息 String xmlBeanid = element.attributeValue("id"); if (StringUtils.isEmpty(xmlBeanid)){ continue; } if(beanId.equals(xmlBeanid)){ String xmlClass = element.attributeValue("class"); //获取class地址信息，使用反射初始化 return xmlClass; } } return null; } //通过反射机制创建对象 初始化 public Object newInstance(String className) throws ClassNotFoundException, IllegalAccessException, InstantiationException { Class<?> classInfo = Class.forName(className); return classInfo.newInstance(); } //解析xml public List<Element> readerXml() throws DocumentException { //解析xml节点信息 SAXReader saxReader = new SAXReader(); Document document = saxReader.read(getResourceAsStream(xmlPath)); //读取根节点信息， Element rootElement = document.getRootElement(); // 读取子节点 返回泛型集合 List<Element> elements = rootElement.elements(); return elements; } //获取当前上下文路径 public InputStream getResourceAsStream(String xmlPath){ InputStream inputStream = this.getClass().getClassLoader().getResourceAsStream(xmlPath); return inputStream; } } package com.wtk.mvcframework.entity; public class User { private Integer id; private String userName; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } } package com.wtk.mvcframework.service; //user 服务层 public interface UserService { public void add(); public void del(); } package com.wtk.mvcframework.service.impl; //user 服务层 import com.wtk.mvcframework.dao.UserDao; import com.wtk.mvcframework.service.UserService; public class UserServiceImpl implements UserService { public void add() { System.out.println("xml实现IOC...."); } // 方法执行完毕之后，才会提交事务 public void del() { // TODO Auto-generated method stub } public UserServiceImpl(){ System.out.println("通过反射机制创建对象。。。"); } }

测试类

package com.wtk.mvcframework.xml.spring; import com.wtk.mvcframework.entity.User; import com.wtk.mvcframework.service.UserService; public class TestSpring { public static void main(String[] args) throws Exception { System.out.println("1"); WTKClassPathXmlApplicationContext app = new WTKClassPathXmlApplicationContext("spring.xml"); System.out.println("2"); UserService bean = (UserService) app.getBean("userService"); System.out.println("3"); bean.add(); System.out.println(bean); } }

效果图