spring 中bean生命周期

Posted 2020-10-08 胡椒孜然

从头开始学习spring(一)

传统编程中，依赖关系比较多的情况下，导致维护成本直线上升，spring 采用Ioc对bean进行管理，减少了开发人员的工作量

正确理解spring bean 的生命周期非常重要

package com.study.spring.beans;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;


public class MyBeanLifeCycle implements BeanNameAware, BeanFactoryAware,
    ApplicationContextAware, BeanPostProcessor, InitializingBean, DisposableBean {

    @Override
    public void setBeanName(String s) {
        System.out.println("bean id : " + s);
    }

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

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        System.out.println("beanFactory : " + beanFactory.toString());
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        System.out.println("applicationContext : " + applicationContext.getApplicationName());
    }

    @Override
    public Object postProcessBeforeInitialization(Object o, String s) throws BeansException {
        System.out.println("postProcessBeforeInitialization : " + s);
        return o;
    }

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

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

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns="http://www.springframework.org/schema/beans"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
  http://www.springframework.org/schema/beans/spring-beans.xsd">


  <bean class="com.study.spring.service.impl.HelloServiceImpl" id="helloService"/>

  <bean id="myBean" class="com.study.spring.beans.MyBeanLifeCycle"/>

</beans>