Why Spring

IOC(Inverse of Control)/DI(Dependency Inverse): 控制反转与依赖注入.
由容器来管理对象之前的依赖关系,而不是对象本身来管理,就叫控制反转.
IOC 是一种思想.Spring的基本思想就是IOC/DI.
Spring 就是一个IOC容器.
解决了工厂泛滥的问题.

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Spring 依赖包:

     Spring_HOME\dist\spring.jar
     Spring_HOME\lib\jakarta-commons\commons-logging.jar
     Spring_HOME\lib\log4j\log4j-1.2.15.jar

Copy spring's configuration file to project src folder.

在相应的类中提供set方法,并在Spring的配置文件中配置一下,让spring提供对象.

   也可能通过构造器进行注入.
   关键点:applicationContext.xml Spring配置文件.

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>

<!--
  - Application context definition for JPetStore's business layer.
  - Contains bean references to the transaction manager and to the DAOs in
  - dataAccessContext-local/jta.xml (see web.xml's "contextConfigLocation").
  -->
<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-2.5.xsd
			http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
			http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
	<bean id="userDao4Mysql" class="com.cnet.spring.dao.UserDao4Mysql"></bean>
	
	<bean  id="userDao4Oracle" class="com.cnet.spring.dao.UserDao4Oracle"></bean>
	
	<bean id="userManager" class="com.cnet.spring.manager.UserManager">
		<property name="userDao" ref="userDao4Mysql"/>
	</bean>
	
</beans>

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