IOC容器

xml封装数据，使用xsl将数据装饰成各种不同的展现形式，xsl可以通过xPath操作xml文件。

一，控制反转与依赖注入

由容器来管理对象之间的依赖关系，就叫“控制反转”或“依赖注入”

二，spring组件安装

1，spring_home/dist/spring.jar

2,spring_home/lib/jakarta-commons/commons-logging.jar

3,spring_home/lib/log4j/log4j-1.2.4.jar

spring的配置文件是\spring-framework-2.0.8\samples\jpetstore\war\WEB-INF/applicationContext.xml拷贝到src下，同时把log4j.properties也拷贝到src目录下。

ioc容器管理对象和对象间的依赖关系

spring IOC容器的关键点：

必须将被管理的对象定义到spring配置文件中，必须定义构造函数或setter方法，让spring将对象注入过来

ioc实现是di依赖注入，ioc就是将变化的对象创建并装备好

三，实例

建立数据层：com.jzq.spring.dao

UserDao类：

package com.jzq.spring.dao;

public class UserDao {
 public void save(String username,String password){};
}

UserDao4MySqlImpl类：

package com.jzq.spring.dao;

public class UserDao4MySqlImpl extends UserDao {
 @Override
 public void save(String username, String password) {
   System.out.println("MySql实现");
 }
}

UserDao4OracleImpl类：

package com.jzq.spring.dao;

public class UserDao4OracleImpl extends UserDao{
 @Override
 public void save(String username, String password) {
  System.out.println("Oracle实现");
 }
}

建立数据管理层：com.jzq.spring.manager

UserManager类：

package com.jzq.spring.manager;

public class UserManager {
 public void save(String username,String password)
 { }
}

UserManagerImpl类：

package com.jzq.spring.manager;

import com.jzq.spring.dao.UserDao;

public class UserManagerImpl extends UserManager {
 private UserDao userDao; 
 //构造方法
// public UserManagerImpl(UserDao userDao)
// {
//  this.userDao=userDao;
// }
 
 //提供的set方法
 public void setUserDao(UserDao userDao)
 {
     this.userDao=userDao; 
 } 
 public void save(String username,String password)
 {
     this.userDao.save(username, password);
 }
}

建立客户端：com.jzq.spring.client

package com.jzq.spring.client;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.jzq.spring.dao.UserDao4OracleImpl;
import com.jzq.spring.manager.UserManager;
import com.jzq.spring.manager.UserManagerImpl;

public class Client {
 public static void main(String[] args)
 {

//普通的调用代码
//  UserManager userManager=new UserManagerImpl(new UserDao4OracleImpl());
//  userManager.save("张三", "123");
    

//使用spring的ioc容器注入调用
  BeanFactory factory=new ClassPathXmlApplicationContext("applicationContext.xml");
     //得到userManager对象并且实例化依赖的对象，并实现依赖的注入
  UserManager userManager=(UserManager)factory.getBean("userManager");
  userManager.save("张三", "123");
 }
}

spring配置文件的注入：

<beans xmlns="http://www.springframework.org/schema/beans"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
      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-2.0.xsd
           http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.0.xsd
           http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.0.xsd">

       <bean id="userDao4MySqlImpl" class="com.jzq.spring.dao.UserDao4MySqlImpl"/>
       <bean id="userDao4OracleImpl" class="com.jzq.spring.dao.UserDao4OracleImpl"></bean>
         
    
       <bean id="userManager" class="com.jzq.spring.manager.UserManagerImpl">
             <!--
                                           构造方法注入  <constructor-arg ref="userDao4MySqlImpl"/>
              -->
             <!-- set注入方法 -->
              <property name="userDao" ref="userDao4OracleImpl"/>
       </bean>
      
</beans>