写一个完整的Spring生命周期例子

一共三个类：

@不能被Spring管理，因为需要通过@Bean的方法加上initMethod和destroyMethod
public class Car implements InitializingBean, DisposableBean {

    public Car() {
        System.out.println("构造函数");
    }

    @PreDestroy
    public void aa() {
        System.out.println("@PreDestroy");
    }

    @PostConstruct
    public void bb() {
        System.out.println("@PostConstruct");
    }

    @Override
    public void destroy() throws Exception {
        System.out.println("重写的DisposableBean方法");
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("重写的InitializingBean方法");
    }

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

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

@Component
public class MainConfigOfLifeCycle {

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

@Component
public class MyBeanPostProcessor implements BeanPostProcessor {

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("postProcessBeforeInitialization  " + bean + "  " + beanName);
#这里return bean和return null是有区别的

return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("postProcessAfterInitialization  " + bean + "  " + beanName);
        return bean;
    }
}

结果如下：

构造函数
postProcessBeforeInitialization  com.config.Car@3ad847f8  car
@PostConstruct  #@PostConstruct：postProcessBeforeInitializatin中return 了bean则有这个输入，但如果return null则没有这个输出
重写的InitializingBean方法
initMethod
postProcessAfterInitialization  com.config.Car@3ad847f8  car

@PreDestroy
重写的DisposableBean方法
destroyMethod