第四讲 --Spring的三种实例化Bean的方式

 

 

三种实例化bean的方式

 

1.使用类构造器实例化
<bean id=“orderService" class="cn.itcast.OrderServiceBean"/>

 

 

2.使用静态工厂方法实例化
<bean id="persionServiceBean2" class="cn.com.xinli.service.impl.PersionServiceBeanFactory" factory-method="createPersionServiceBean"/>

 

public class PersionServiceBeanFactory
{
 public static PersionServiceBean createPersionServiceBean()
 {
  return new PersionServiceBean();
 }
}

 

例子:

 

(1).首先写工厂类.他其中包含产生我们的业务bean的方法

package cn.com.xinli.service.impl;


public class PersionServiceBeanFactory
{
	public static PersionServiceBean createPersionServiceBean()
	{
		return new PersionServiceBean();
	}
}

 

(2).改写beans.xml :包含工厂类类名和产生业务bean的方法名字

 

 <bean id="persionServiceBean2" class="cn.com.xinli.service.impl.PersionServiceBeanFactory" factory-method="createPersionServiceBean"/>

 

 (3) 测试

 

ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
		PersionSevice ps=(PersionSevice)ctx.getBean("persionServiceBean2");
		                                             
		ps.save();

 (4) 结果

 

2009-05-24 14:34:00,781  INFO (PersionServiceBean.java:12) - 我是save()方法!

 

3.使用实例工厂方法实例化:

 

<bean id="PersionServiceBeanFactory" class="cn.com.xinli.service.impl.PersionServiceBeanFactory"></bean>
    <bean id="persionServiceBean3" factory-bean="PersionServiceBeanFactory" factory-method="createPersionServiceBean2"></bean>

 

public  PersionServiceBean createPersionServiceBean2()
 {
  return new PersionServiceBean();
 }

 

例子:

 

(1). 首先写工厂类.他其中包含产生我们的业务bean的方法 ,在已有代码的基础上

package cn.com.xinli.service.impl;


public class PersionServiceBeanFactory
{
	public static PersionServiceBean createPersionServiceBean()
	{
		return new PersionServiceBean();
	}
	
	public  PersionServiceBean createPersionServiceBean2()
	{
		return new PersionServiceBean();
	}
	
}

 

 

(2).改写beans.xml :写两个bean,一个是工厂bean,一个是利用工厂bean产生业务bean的bean.

 

<bean id="PersionServiceBeanFactory" class="cn.com.xinli.service.impl.PersionServiceBeanFactory"></bean>
    <bean id="persionServiceBean3" factory-bean="PersionServiceBeanFactory" factory-method="createPersionServiceBean2"></bean>

 

 (3) 测试

 

ClassPathXmlApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
		PersionSevice ps=(PersionSevice)ctx.getBean("persionServiceBean3");
		                                             
		ps.save();

 (4) 结果

 

2009-05-24 14:49:17,812  INFO (PersionServiceBean.java:12) - 我是save()方法!

 

 (5) 注意,其实方式2和方式3的区别就在 工厂类中是如何产生业务bean的,方式2是static方式,方式3不是