Spring注解驱动开发-Bean的生命周期

bean的生命周期：bean创建—初始化----销毁的过程
容器管理bean的生命周期：我们可以自定义初始化和销毁方法；容器在bean进行到当>前生命周期的时候来调用我们自定义的初始化和销毁方法

一、指定初始化和销毁方法

通过@Bean指定init-method和destroy-method；
如果是Bean是多例的，spring只负责创建Bean，在容器关闭的时候并不会销毁bean

public class Car {

    public Car(){
        System.out.println("Car Constructor ......");
    }

    public void init(){
        System.out.println("Car initial ......");
    }

    public void destroy(){
        System.out.println("Car destroy ......");
    }
}

@Bean(initMethod = "init",destroyMethod = "destroy")
    public Car car(){
        return new Car();
    }

 @Test
    public  void test01(){
        ApplicationContext applicationContext = new AnnotationConfigApplicationContext(BeanLifeCyleConfig.class);
        System.out.println("IOC容器创建完成");
        Car car = applicationContext.getBean(Car.class);
        ((AnnotationConfigApplicationContext) applicationContext).close();

    }

二、通过让Bean实现InitializingBean（定义初始化逻辑） DisposableBean（定义销毁逻辑

public class Student implements InitializingBean ,DisposableBean {
    public Student() {
        System.out.println("Student Constructor ......");
    }
    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("Student initial ........");
    }
    @Override
    public void destroy() throws Exception {
        System.out.println("Student destroy ...........");
    }
}

三、可以使用JSR250；

	@PostConstruct：在bean创建完成并且属性赋值完成；来执行初始化方法
	@PreDestroy：在容器销毁bean之前通知我们进行清理工作

@Component
public class Dog implements ApplicationContextAware {
	//@Autowired
	private ApplicationContext applicationContext;
	public Dog(){
		System.out.println("dog constructor...");
	}
	//对象创建并赋值之后调用
	@PostConstruct
	public void init(){
		System.out.println("[email protected]");
	}
	//容器移除对象之前
	@PreDestroy
	public void detory(){
		System.out.println("[email protected]");
	}
	@Override
	public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
		this.applicationContext = applicationContext;
	}
}

四 、BeanPostProcessor【interface】：bean的后置处理器；

	在bean初始化前后进行一些处理工作；
	postProcessBeforeInitialization:在初始化之前工作
	postProcessAfterInitialization:在初始化之后工作

public class MyBeanPostProcessor implements BeanPostProcessor {

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

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

}