Static factory configuration bean

Create a bean by calling a static factory method

Calling a static factory method to create a bean is to encapsulate the process of object creation into a static method . When the client needs the object, it only needs to simply call the static method without caring about the details of creating the object.

To declare a bean created by a static method, you need to specify the class of the factory method in the bean's class attribute, and specify the name of the factory method in the factory-method attribute. Finally, use the <constrctor-arg> element for the method Pass method parameters.

<?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">
	<!-- 静态工厂配置bean 
		class: 静态工厂类
		factroy-method: 静态工厂方法.
	-->
	<bean id="car" class="com.learn.spring.factory.StaticObjectFactory"
		factory-method="getCar" >
		<constructor-arg value="audi"></constructor-arg>	
	 </bean>
</beans>

package com.learn.spring.factory;

import java.util.HashMap;
import java.util.Map;

import com.learn.spring.autowire.Car;

/**
 * 获取Car对象的工厂.
 * Car car = StaticObjectFactory.getCar("audi");
 */
public  class StaticObjectFactory {
	
	private static Map<String,Car> cars = new HashMap<String,Car>();
	
	static{
		cars.put("audi", new Car("Audi", 450000));
		cars.put("bmw", new Car("bmw",500000));
		
	}
	/**
	 * 静态工厂方法
	 */
	public static Car getCar(String carName){
		return cars.get(carName);
	}
}

package com.learn.spring.factory;

import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.learn.spring.autowire.Car;

public class Main {
	public static void main(String[] args) {
		ClassPathXmlApplicationContext ctx = 
				new ClassPathXmlApplicationContext("spring-factory.xml");
		Car car =(Car) ctx.getBean("car");
		System.out.println(car);
	}
}