Spring、实例化Bean的三种方法

1、使用类构造器进行实例化

<bean id="personIService" class="cn.server.impl.PersonServiceImpl" />

测试代码：

@Test
public void test() {
ApplicationContext ac = new ClassPathXmlApplicationContext("beans.xml");
PersonIService personIService=(PersonIService)ac.getBean("personIService");
personIService.helloSpring();
}

2、使用静态工厂实例化
public class BeanFactory {
public static PersonServiceImpl createPersonServiceImpl(){
return new PersonServiceImpl();
}
}

<bean id="personIService2" class="cn.BeanFactory" factory-method="createPersonServiceImpl" />

测试代码：
@Test
public void test3() {
ApplicationContext ac = new ClassPathXmlApplicationContext("beans.xml");
PersonIService personIService=(PersonIService)ac.getBean("personIService2");
personIService.helloSpring();
}

3、使用实例化工厂实例化
public class BeanFactory {
public PersonServiceImpl createPersonServiceImpl2(){
return new PersonServiceImpl();
}
}

<bean id="beanFactory" class="cn.BeanFactory"/>
<bean id="personIService3" factory-bean="beanFactory"  factory-method="createPersonServiceImpl2" />

测试代码：
@Test
public void test4() {
ApplicationContext ac = new ClassPathXmlApplicationContext("beans.xml");
PersonIService personIService=(PersonIService)ac.getBean("personIService3");
personIService.helloSpring();
}