spring ioc 与 di 配置文件

3.spring中的概念
ioc: 反转控制. 创建对象的方式反转了.从我们自己创建对象,反转给spring(程序)来创建.

di: 依赖注入.将必须的属性注入到对象当中.是实现ioc思想必须条件.

beanFactory与ApplicationContext

Demo.java

package cn.itcast.c_injection;

import java.util.Collection;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import cn.itcast.bean.User;

public class Demo {
	@Test
	public void fun1() {
		//1 创建容器对象
		ApplicationContext ac=new ClassPathXmlApplicationContext("cn/itcast/c_injection/applicationContext.xml");
		//2 向容器“要” user对象
		User u=(User)ac.getBean("user");
		//3 打印user对象
		System.out.println(u);
	}
	@Test
	public void fun2() {
		//1 创建容器对象
		ApplicationContext ac=new ClassPathXmlApplicationContext("cn/itcast/c_injection/applicationContext.xml");
		//2 向容器“要” user对象
		User u=(User)ac.getBean("user2");
		//3 打印user对象
		System.out.println(u);
	}
	

	@Test
	public void fun3() {
		//1 创建容器对象
		ApplicationContext ac=new ClassPathXmlApplicationContext("cn/itcast/c_injection/applicationContext.xml");
		//2 向容器“要” user对象
		CollectionBean cb=(CollectionBean)ac.getBean("cb");
		//3 打印user对象
		System.out.println(cb);
	}
}

User.java

package cn.itcast.bean;

public class User {
	private String name;
	private Integer age;
	private Car car;
	
	
	
	public User() {
		System.out.println("User对象空参数构造方法");
	}
	
	public User(String name, Car car) {
		System.out.println("public User(String name, Car car)");
		this.name = name;
		this.car = car;
	}
	public User(Car car,String name) {
		System.out.println("User(Car car,String name)===============================");
		this.name = name;
		this.car = car;
	}

	@Override
	public String toString() {
		return "User [name=" + name + ", age=" + age + ", car=" + car + "]";
	}
	public Car getCar() {
		return car;
	}

	public void setCar(Car car) {
		this.car = car;
	}

	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	
}

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd ">

	<!-- set方式注入： -->
	<bean name="user" class="cn.itcast.bean.User">
	<!-- 为user对象中名为name的属性注入tom作为值 -->
	<property name="name" value="tom"></property>
	<property name="age" value="18"></property>
	<!-- 为car属性注入下方配置的car对象 -->
	<property name="car" ref="car"></property>
	</bean>
	
	<!-- 将car对象配置到容器中 -->
	<bean name="car" class="cn.itcast.bean.Car">
	<property name="name" value="兰博基尼"></property>
	<property name="color" value="红色"></property>
	</bean>
	
	<!-- ======================================== -->
	<!-- 构造函数注入
	<bean name="user2" class="cn.itcast.bean.User">
	index="1" type="cn.itcast.bean.Car"
	<constructor-arg name="name" value="jerry" ></constructor-arg>
	<constructor-arg name="car" ref="car"></constructor-arg>
	</bean> -->
	
	<!-- ======================================== -->
	<!-- 复杂类型注入 -->
	<!-- array注入 -->
	<bean name="cb" class="cn.itcast.c_injection.CollectionBean">
		<!-- 如果数组中只准备注入一个值 -->
		<!-- <property name="arr" value="tom"></property> -->
		<!-- 注入多个值 -->
		<property name="arr">
			<array>
				<value>tom</value>
				<value>jerry</value>
				<ref bean="user"/>
			</array>
		</property>
	</bean>
</beans>