spring IOC之 xml 配置管理

bean.xml配置元数据

beans.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"
	xsi:schemaLocation="http://www.springframework.org/schema/beans
		https://www.springframework.org/schema/beans/spring-beans.xsd">

	<bean id="..." class="...">
		<!-- collaborators and configuration for this bean go here -->
	</bean>

	<bean id="..." class="...">
		<!-- collaborators and configuration for this bean go here -->
	</bean>

	<!-- more bean definitions go here -->

</beans>

示例： beans.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"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
		https://www.springframework.org/schema/beans/spring-beans.xsd">

    <bean id="hello" class="com.chen.pojo.Hello">
        <!-- collaborators and configuration for this bean go here -->
        <!--
        value 是基本的值
        ref 是引用spring容器中创建好的对象
        -->
        <property name="name" value="XiaoMing"/>
    </bean>
    <bean id="userDaoMysql" class="com.chen.dao.UserDaoMysql"/>
    <bean id="userDaoOracle" class="com.chen.dao.UserDaoOracle"/>
    <bean id="userDaoSqlServer" class="com.chen.dao.UserDaoSqlServer"/>
    <bean id="serviceDemo" class="com.chen.service.ServiceDemo">
        <!-- collaborators and configuration for this bean go here -->
        <!--
        value 是基本的值
        ref 是引用spring容器中创建好的对象

        上面先使spring 生成 userDaoMysql、userDaoOracle、userDaoSqlServer 三个对象
        然后再添加 bean serviceDemo，生成 serviceDemo 对象，然后设置属性property，ServiceDemo 类中一定要实现 setUser 方法，
        然后ref引用spring容器中创建好的对象
        -->
        <property name="user" ref="userDaoSqlServer"/>
    </bean>
</beans>

MyTest.java

import com.chen.service.ServiceDemo;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MyTest {
    public static void main(String[] args) {
        // Spring 的获取上下文容器，读取beans.xml 配置文件，由 spring 创建、管理对象
        ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml");
        ServiceDemo hello = (ServiceDemo) context.getBean("serviceDemo");
        hello.getUser();
    }
}