Spring1 Bean实例化

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本文介绍了Spring框架中Bean的三种实例化方法：普通方法、静态工厂方法和工厂方法，并提供了具体的实现示例。

1. Bean实例化的方法
a. 普通方法

public class PersonServiceBean implements PersonService {
	public void save(){
		System.out.println("我是save()方法");
	}
}

<bean id="personService" class="cn.itcast.service.impl.PersonServiceBean"></bean>

	@Test 
	public void instanceSpring(){
		ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
		PersonService personService = (PersonService)ctx.getBean("personService");
		personService.save();
	}

b. 静态工厂方法

public class PersonServiceBeanFactory {
	public static PersonServiceBean createPersonServiceBean(){
		return new PersonServiceBean();
	}
}

<bean id="personService2" class="cn.itcast.service.impl.PersonServiceBeanFactory" 
          factory-method="createPersonServiceBean"/>

	@Test 
	public void instanceSpring(){
		ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
		PersonService personService = (PersonService)ctx.getBean("personService2");
		personService.save();
	}

c. 工厂方法

public class PersonServiceBeanFactory {	
	public PersonServiceBean createPersonServiceBean2(){
		return new PersonServiceBean();
	}
}

<bean id="personServiceFactory" class="cn.itcast.service.impl.PersonServiceBeanFactory"/>
          <bean id="personService3" factory-bean="personServiceFactory" factory-method="createPersonServiceBean2"/>

	@Test 
	public void instanceSpring(){
		ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
		PersonService personService = (PersonService)ctx.getBean("personService3");
		personService.save();
	}