Spring中Bean生命周期

Spring中Bean生命周期

1、声明周期

2、代码实现

package com.example.second.config;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessor;
import org.springframework.stereotype.Component;

/**
 * 实现InstantiationAwareBeanPostProcessor
 */
@Component
public class MyInstantiationAwareBeanPostProcessor implements InstantiationAwareBeanPostProcessor {

    @Override
    public Object postProcessBeforeInstantiation(Class<?> BeanClass, String BeanName) throws BeansException {
        System.out.println("InstantiationAwareBeanPostProcessor的before()执行了...." + BeanName);
        return null;
    }

    @Override
    public boolean postProcessAfterInstantiation(Object Bean, String BeanName) throws BeansException {
        System.out.println("InstantiationAwareBeanPostProcessor的after()执行了...." + BeanName);
        return false;
    }
}

package com.example.second.config;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
import org.springframework.stereotype.Component;

/**
 * 实现BeanPostProcessor
 */
@Component
public class MyBeanPostProcessor implements BeanPostProcessor {
    @Override
    public Object postProcessBeforeInitialization(Object Bean, String BeanName) throws BeansException {
        System.out.println("BeanPostProcessor的before()执行了...." + BeanName);
        return Bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object Bean, String BeanName) throws BeansException {
        System.out.println("BeanPostProcessor的after()执行了...." + BeanName);
        return Bean;
    }
}

package com.example.second.config;

import lombok.AllArgsConstructor;
import lombok.Data;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;

import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;

/**
 * Bean定义
 */
@Data
@AllArgsConstructor
public class Boo implements InitializingBean, DisposableBean, BeanNameAware {

    private Long id;
    private String name;

    public Boo() {
        System.out.println("boo实例化构造方法执行了...");
    }

    @PostConstruct
    public void initMethod() {
        System.out.println("boo执行初始化init()方法了...");
    }

    @PreDestroy
    public void destroyMethod() {
        System.out.println("boo执行初始化destroy()方法了...");
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        System.out.println("boo执行InitializingBean的afterPropertiesSet()方法了...");
    }

    @Override
    public void destroy() throws Exception {
        System.out.println("boo执行DisposableBean的destroy()方法了...");
    }

    @Override
    public void setBeanName(String name) {
        System.out.println("boo执行BeanNameAware的setBeanName()方法了...");
    }
}

package com.example.second.config;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

@ComponentScan(basePackages = {"com.example.second.config"})
@Configuration
public class MyConfig {

    @Bean
    public Boo boo() {
        return new Boo();
    }

    public static void main(String[] args) {

        AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MyConfig.class);
        String[] BeanDefinitionNames = applicationContext.getBeanDefinitionNames();
        // 遍历Spring容器中的BeanName
        for (String BeanDefinitionName : BeanDefinitionNames) {
            System.out.println("["+BeanDefinitionName+"]");
        }
        // 这里调用的applicationContext的close()触发Bean的销毁回调方法
        // 当我们执行容器applicationContext的关闭方法close()会触发调用bean的销毁回调方法
        applicationContext.close();
    }
}

# 输出
......
09:19:11.042 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'myBeanPostProcessor'
09:19:11.047 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'myInstantiationAwareBeanPostProcessor'
09:19:11.052 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'myConfig'
InstantiationAwareBeanPostProcessor的before()执行了....myConfig
InstantiationAwareBeanPostProcessor的after()执行了....myConfig
BeanPostProcessor的before()执行了....myConfig
BeanPostProcessor的after()执行了....myConfig
09:19:11.052 [main] DEBUG org.springframework.beans.factory.support.DefaultListableBeanFactory - Creating shared instance of singleton bean 'boo'
InstantiationAwareBeanPostProcessor的before()执行了....boo
boo实例化构造方法执行了...
InstantiationAwareBeanPostProcessor的after()执行了....boo
boo执行BeanNameAware的setBeanName()方法了...
BeanPostProcessor的before()执行了....boo
boo执行初始化init()方法了...
boo执行InitializingBean的afterPropertiesSet()方法了...
BeanPostProcessor的after()执行了....boo
[org.springframework.context.annotation.internalConfigurationAnnotationProcessor]
[org.springframework.context.annotation.internalAutowiredAnnotationProcessor]
[org.springframework.context.annotation.internalCommonAnnotationProcessor]
[org.springframework.context.event.internalEventListenerProcessor]
[org.springframework.context.event.internalEventListenerFactory]
[myConfig]
[myBeanPostProcessor]
[myInstantiationAwareBeanPostProcessor]
[boo]
09:19:11.082 [main] DEBUG org.springframework.context.annotation.AnnotationConfigApplicationContext - Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@6504e3b2, started on Mon Mar 25 09:19:10 CST 2024
boo执行初始化destroy()方法了...
boo执行DisposableBean的destroy()方法了...