Spring IOC容器对bean的生命周期进行管理的过程

1.通过构造器或者工厂方法创建bean的实例

2.为bean的属性设置值和对其他bean的引用

3.将bean的实例传递给bean的后置处理器BeanPostProcessor的postProcessBeforeInitialization方法

4.调用bean的初始化方法

5.调用bean的后置处理器BeanPostProcessor的postProcessAfterInitialization方法

6.使用bean容器

7.调用bean的销毁方法

创建Car类 定义以下方法

 public class Car {
 
     public Car() {
         System.out.println("create car");
     }
 
     private String brand;
 
     public void setBrand(String brand) {
         System.out.println("set brand");
         this.brand = brand;
     }
 
     public void init() {
         System.out.println("init ...");
     }
 
     public void destroy() {
         System.out.println("destroy...");
     }
 
     @Override
     public String toString() {
         return "Car [brand=" + brand + "]";
     }
 
 }

创建一个类实现BeanPostProcessor接口  重写两个方法

 public class MyBeanPostProcessor implements BeanPostProcessor{
 
     @Override
     public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
         // TODO Auto-generated method stub
         System.out.println("postProcessBeforeInitialization"+bean+","+beanName);
         return bean;
     }
 
     @Override
     public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
         // TODO Auto-generated method stub
         System.out.println("postProcessAfterInitialization"+bean+","+beanName);
         return bean;
     }
 
 }

在applicationContext.xml中配置bean

 <bean id="car" class="beancycle.Car"
       init-method="init" destroy-method="destroy">
           <property name="brand" value="aodi"></property>
       </bean>
 
       <bean class="beancycle.MyBeanPostProcessor"></bean>

编写main方法测试

 public static void main(String[] args) {
         ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
         Car car = (Car)context.getBean("car");
         car.destroy();
 
     }

输出结果如下

create car
set brand
postProcessBeforeInitializationCar [brand=aodi],car
init ...
postProcessAfterInitializationCar [brand=aodi],car
destroy...