spring 配置bean[通俗易懂]

package com.coslay.beans;

public class Car {
	private String brand;
	private String corp;
	private double price;
	private int maxSpeed;
	public Car(String brand, String corp, double price) {
		super();
		this.brand = brand;
		this.corp = corp;
		this.price = price;
	}
	
	
	
	public Car(String brand, String corp, int maxSpeed) {
		super();
		this.brand = brand;
		this.corp = corp;
		this.maxSpeed = maxSpeed;
	}



	public String toString() {
		return "Car [brand=" + brand + ", corp=" + corp + ", price=" + price
				+ ", maxSpeed=" + maxSpeed + "]";
	}
}

package com.coslay.beans;

public class HelloWorld {
	private String name;
	
	public void setName(String name){
		System.out.println("setName: ");
		this.name = name;
	}
	
	public void hello(){
		System.out.println("hello: "+name);
	}
	
	public HelloWorld(){
		System.out.println("HelloWorld's Constructor...");
	}
}

package com.coslay.spring;

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

import com.coslay.beans.Car;
import com.coslay.beans.HelloWorld;

public class Main {
	public static void main(String[] args) {
		
//		//创建HelloWorld的一个对象
//		HelloWorld helloWorld = new HelloWorld();
//		//为name属性赋值
//		helloWorld.setName("yyz");
//      使用spring以后，这两步可交给spring完毕		
		
		
		//1.创建spirng的IOC容器对象
		//ApplicationContext 代表IOC容器
		//ClassPathXmlApplicationContext:是ApplicationContext接口的实现类，该实现类从类路径下载入配置文件
		ApplicationContext ctx = new ClassPathXmlApplicationContext("applicationContext.xml");
		//创建容器的时候会调用全部bean对象的构造器，并为bean注入（赋值）
		
		//2.从IOC容器中获取Bean实例
		//利用id定位到IOC容器中的bean
	    //HelloWorld helloWorld = (HelloWorld) ctx.getBean("helloWorld");
		//利用类型返回IOC容器中的Bean。但要求IOC容器中必须仅仅能有一个该类型的Bean
		//HelloWorld helloWorld = ctx.getBean(HelloWorld.class);
		
		//调用hello方法
		//helloWorld.hello();
		
		Car car = (Car) ctx.getBean("car");
		System.out.println(car);
		
		Car car2 = (Car) ctx.getBean("car2");
		System.out.println(car2);
	}
}

<?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 http://www.springframework.org/schema/beans/spring-beans.xsd">		<!-- 		配置bean		class：bean的全类名，通过反射的方式在IOC容器中创建Bean，所以要求Bean中必须有无參数的构造器 		id：标识容器中的bean。id唯一	-->	<bean id="helloWorld" class="com.coslay.beans.HelloWorld">		<property name="name" value="yyz"></property>	</bean>		<!-- 通过构造方法来配置bean的属性 -->	<bean id="car" class="com.coslay.beans.Car">		<constructor-arg value="Audi" index="0"></constructor-arg>		<constructor-arg value="ShangHai" index="1"></constructor-arg>		<constructor-arg value="300000" type="double"></constructor-arg>	</bean>		<!-- 使用构造器注入属性值能够指定參数的位置和參数的类型，以区分重载的构造器 -->	<bean id="car2" class="com.coslay.beans.Car">		<constructor-arg value="Baoma" type="java.lang.String"></constructor-arg>		<constructor-arg value="Shanghai" type="java.lang.String"></constructor-arg>		<constructor-arg value="240" type="int"></constructor-arg>	</bean></beans>