Spring中的Bean实现的创建三种方式

Spring中的Bean实现的创建方式

1.调用构造器"new"一个Bean实现

 

<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:aop="http://www.springframework.org/schema/aop"xmlns:tx="http://www.springframework.org/schema/tx"xsi:schemaLocation="http://www.springframework.org/schema/beans           http://www.springframework.org/schema/beans/spring-beans-2.5.xsd           http://www.springframework.org/schema/context           http://www.springframework.org/schema/context/spring-context-2.5.xsd           http://www.springframework.org/schema/aop           http://www.springframework.org/schema/aop/spring-aop-2.5.xsd           http://www.springframework.org/schema/tx            http://www.springframework.org/schema/tx/spring-tx-2.5.xsd"><!-- 采用Set注入的方式依赖 --><bean id="chinese" class="com.jask.spring.Chinese"><property name="meiGou"><ref local="meiGou" /></property></bean><bean id="meiGou" class="com.jask.spring.MeiGou"></bean></beans>

 

public class Chinese implements Person{private Person meiGou;public Chinese(){System.out.println("Chinese init");}public void say(){meiGou.say();}public void sayBye(){meiGou.sayBye();}public void setMeiGou(MeiGou meiGou){System.out.println("Chinese‘s 依赖关系");this.meiGou = meiGou;}}

 

public class MeiGou implements Person{private Chinese chinese;public MeiGou(){System.out.println("MeiGou init");}public void say(){System.out.println("MeiGou Say");}public void sayBye(){System.out.println("MeiGou sayBye");}public void setChinese(Chinese chinese){this.chinese = chinese;}}

 

public class TestMain{public static void main(String[] args){ApplicationContext ctx = new ClassPathXmlApplicationContext("spring.xml");BeanFactory factory = (BeanFactory)ctx;Chinese chinese =  (Chinese) factory.getBean("chinese");chinese.say();}}

 

结果：

Chinese init
MeiGou init
Chinese‘s 依赖关系
MeiGou Say

 

实例执行顺序：

首先去实现一个Chinese对象的构造器

再去实现依赖的对象MeiGou构造器

然后在去注入依赖关系

最后返回依赖的实现

 

2.采用静态工厂方法创建Bean

只修改了Spring配置文件

<!-- Bean的静态工厂创建实例 --><bean id="chinese" class="com.jask.spring.Chinese"><property name="meiGou"><ref local="meiGou"/></property></bean><bean id="meiGou" class="com.jask.spring.StaticFactory" factory-method="getPerson"><constructor-arg><value>meiGou</value></constructor-arg></bean>

 

3.采用实现工厂方法创建Bean

只修改了Spring配置文件

<!-- Bean的实现工厂创建实例 --><bean id="staticFactoryBean" class="com.jask.spring.StaticFactory"></bean><bean id="chinese" class="com.jask.spring.Chinese"><property name="meiGou"><ref local="meiGou"/></property></bean><bean id="meiGou" factory-bean="staticFactoryBean" factory-method="getPerson"><constructor-arg><value>meiGou</value></constructor-arg></bean>