spring bean 靜態工廠例項化

在工廠類中建立一個靜態方法來例項化物件。在配置bean時，class指定靜態工廠類，同時還需要使用factory-method屬性指定工廠類中的靜態方法。

1.建立工廠類BeanStaticFactory

package instance;

public class BeanStaticFactory {
	private static BeanClass beanInstance = new BeanClass("呼叫靜態工廠方法例項化bean");
	public static BeanClass createInstance() {
		return beanInstance;
	}
}
 

2.編輯配置檔案

<?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">

    <bean id="constructorInstance" class="instance.BeanClass">
        <!-- collaborators and configuration for this bean go here -->
    </bean>
    
    <!-- 靜態工廠例項化bean  -->
	<bean id="staticFacoryInstance" class="instance.BeanStaticFactory" factory-method="createInstance">
	
	</bean>
    

</beans>
 

3.新增測試程式碼

package test;

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

import instance.BeanClass;

public class TestInstance {
	public static void main(String[] args) {
		ApplicationContext appCon = new ClassPathXmlApplicationContext("applicationContext.xml");
		
		BeanClass b1 = (BeanClass)appCon.getBean("constructorInstance");
		System.out.println(b1+b1.message);
		
		//測試靜態工廠例項化bean
		BeanClass b2 =(BeanClass)appCon.getBean("staticFacoryInstance");
		System.out.println(b2+b2.message);
	}
}