前言
記得以前的時候，每次提起Spring中的bean相關的生命週期時，內心都無比的恐懼，因為好像有很多，自己又理不清楚：什麼beanFactory啊，aware介面啊，beanPostProcessor啊，afterPropertiesSet啊，initMethod啊等等。
今天終於理清這些關係了，並且又新增了對postConstruct和lifecycle的理解。
執行順序
- 首先是 BeanFactoryPostProcessor，它是針對所有bean的definition的，只執行一次
下面是針對每個bean的初始
- 實現了一系列aware介面的，比如BeanNameAware，ApplicationContextAware，呼叫其set方法
- 執行BeanPostProcessor的postProcessBeforeInitialization方法
- 帶有@PostConstruct註解的方法
- 實現InitializingBean介面的afterPropertiesSet方法
- 指定的initMethod方法
- 執行BeanPostProcessor的postProcessAfterInitialization方法
- 實現了SmartLifecycle介面的start方法(實現Lifecycle介面的不會自動呼叫，需要顯式的呼叫start方法)
下面是針對每個bean的銷燬
- 實現了SmartLifecycle介面的stop方法(實現Lifecycle介面的不會自動呼叫，需要顯式的呼叫stop方法)
- 帶有@PreDestroy註解的方法
- 實現DisposableBean介面的destroy方法
- 指定的destroyMethod方法
目前就想到這麼多了，其他的麻煩在評論區留言呀~
程式碼例項
bean實體類
/**
* @date: 2020-07-22
*
* 一個簡單的列舉類
*/
public enum BeanType {
NORMAL, LIFECYCLE, SMART_LIFECYCLE;
}
import javax.annotation.PostConstruct;
import javax.annotation.PreDestroy;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
/**
* @author: lihui
* @date: 2020-07-22
* 一個簡單的bean
*/
@Slf4j
public class NormalBean implements BeanNameAware, ApplicationContextAware, InitializingBean, DisposableBean {
private BeanType beanType;
public NormalBean() {
this(BeanType.NORMAL);
}
public NormalBean(BeanType beanType) {
this.beanType = beanType;
}
@PostConstruct
public void postConstruct() {
log.info("{}, postConstruct", beanType);
}
@Override
public void afterPropertiesSet() throws Exception {
log.info("{}, afterPropertiesSet", beanType);
}
public void initMethod() {
log.info("{}, initMethod", beanType);
}
@PreDestroy
public void preDestroy() {
log.info("{}, preDestroy", beanType);
}
@Override
public void destroy() throws Exception {
log.info("{}, destroy", beanType);
}
public void destroyMethod() {
log.info("{}, destroyMethod", beanType);
}
@Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
log.info("setApplicationContext, applicationContext : {}", applicationContext);
}
@Override
public void setBeanName(String name) {
log.info("setBeanName, bean name : {}", name);
}
}
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.Lifecycle;
/**
* @author: lihui
* @date: 2020-07-22
* 實現了Lifecycle的一個bean
*/
@Slf4j
public class LifecycleBean extends NormalBean implements Lifecycle {
private volatile boolean running = false;
public LifecycleBean() {
super(BeanType.LIFECYCLE);
}
@Override
public void start() {
log.info("start");
running = true;
}
@Override
public void stop() {
log.info("stop");
running = false;
}
@Override
public boolean isRunning() {
return running;
}
}
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.SmartLifecycle;
/**
* @author: lihui
* @date: 2020-07-22
* 實現了SmartLifecycle的一個bean
*/
@Slf4j
public class SmartLifecycleBean extends NormalBean implements SmartLifecycle {
private volatile boolean running = false;
public SmartLifecycleBean() {
super(BeanType.SMART_LIFECYCLE);
}
@Override
public void start() {
log.info("start");
running = true;
}
@Override
public void stop() {
log.info("stop");
running = false;
}
@Override
public boolean isRunning() {
return running;
}
}
配置類
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
/**
* @author: lihui
* @date: 2020-07-25
*/
@Slf4j
public class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
log.info("postProcessBeanFactory, beanFactory:{}", beanFactory);
}
}
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
/**
* @author: lihui
* @date: 2020-07-25
*/
@Slf4j
public class MyBeanPostProcessor implements BeanPostProcessor {
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
log.info("postProcessBeforeInitialization, bean:{}", beanName);
return bean;
}
@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
log.info("postProcessAfterInitialization, bean:{}", beanName);
return bean;
}
}
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.SmartLifecycle;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
/**
* @author: lihui
* @date: 2020-07-22
*/
@Configuration
@Slf4j
public class Config {
@Bean(initMethod = "initMethod", destroyMethod = "destroyMethod")
public NormalBean normalBean() {
return new NormalBean();
}
@Bean(initMethod = "initMethod", destroyMethod = "destroyMethod")
public LifecycleBean lifecycleBean() {
return new LifecycleBean();
}
@Bean(initMethod = "initMethod", destroyMethod = "destroyMethod")
public SmartLifecycle smartLifecycle() {
return new SmartLifecycleBean();
}
@Bean
public static MyBeanFactoryPostProcessor myBeanFactoryPostProcessor() {
return new MyBeanFactoryPostProcessor();
}
@Bean
public static MyBeanPostProcessor myBeanPostProcessor() {
return new MyBeanPostProcessor();
}
}
Main類
import lombok.extern.slf4j.Slf4j;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
/**
* @author: lihui
* @date: 2020-07-22
*/
@Slf4j
public class Main {
public static void main(String[] args) throws InterruptedException {
ConfigurableApplicationContext ctx = new AnnotationConfigApplicationContext(Config.class);
ctx.registerShutdownHook();
Thread.sleep(5000);
log.info("line ----------------------------- line");
ctx.start();
ctx.stop();
log.info("line ----------------------------- line");
}
}
結果說明
結果正如前面所說的執行順序一致，主要注意的就是Lifecycle介面和SmartLifecycle介面，只有實現了SmartLifecycle介面的bean在初始化時才會被自動呼叫，而實現了Lifecycle介面的除非顯式呼叫start和stop方法才會被呼叫。
502 2020-07-26 23:43:41.808 [main] INFO c.e.d.s.a.i.l.MyBeanFactoryPostProcessor - postProcessBeanFactory, beanFactory:org.springframework.beans.factory.support.DefaultListableBeanFactory@55ca8de8: defining beans [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,config,normalBean,lifecycleBean,smartLifecycle,myBeanFactoryPostProcessor,myBeanPostProcessor]; root of factory hierarchy
520 2020-07-26 23:43:41.826 [main] INFO c.e.d.s.a.i.l.MyBeanPostProcessor - postProcessBeforeInitialization, bean:config
520 2020-07-26 23:43:41.826 [main] INFO c.e.d.s.a.i.l.MyBeanPostProcessor - postProcessAfterInitialization, bean:config
536 2020-07-26 23:43:41.842 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - setBeanName, bean name : normalBean
536 2020-07-26 23:43:41.842 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - setApplicationContext, applicationContext : org.springframework.context.annotation.AnnotationConfigApplicationContext@7cd62f43, started on Sun Jul 26 23:43:41 CST 2020
536 2020-07-26 23:43:41.842 [main] INFO c.e.d.s.a.i.l.MyBeanPostProcessor - postProcessBeforeInitialization, bean:normalBean
536 2020-07-26 23:43:41.842 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - NORMAL, postConstruct
536 2020-07-26 23:43:41.842 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - NORMAL, afterPropertiesSet
536 2020-07-26 23:43:41.842 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - NORMAL, initMethod
537 2020-07-26 23:43:41.843 [main] INFO c.e.d.s.a.i.l.MyBeanPostProcessor - postProcessAfterInitialization, bean:normalBean
538 2020-07-26 23:43:41.844 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - setBeanName, bean name : lifecycleBean
538 2020-07-26 23:43:41.844 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - setApplicationContext, applicationContext : org.springframework.context.annotation.AnnotationConfigApplicationContext@7cd62f43, started on Sun Jul 26 23:43:41 CST 2020
538 2020-07-26 23:43:41.844 [main] INFO c.e.d.s.a.i.l.MyBeanPostProcessor - postProcessBeforeInitialization, bean:lifecycleBean
538 2020-07-26 23:43:41.844 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - LIFECYCLE, postConstruct
540 2020-07-26 23:43:41.846 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - LIFECYCLE, afterPropertiesSet
540 2020-07-26 23:43:41.846 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - LIFECYCLE, initMethod
540 2020-07-26 23:43:41.846 [main] INFO c.e.d.s.a.i.l.MyBeanPostProcessor - postProcessAfterInitialization, bean:lifecycleBean
541 2020-07-26 23:43:41.847 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - setBeanName, bean name : smartLifecycle
541 2020-07-26 23:43:41.847 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - setApplicationContext, applicationContext : org.springframework.context.annotation.AnnotationConfigApplicationContext@7cd62f43, started on Sun Jul 26 23:43:41 CST 2020
541 2020-07-26 23:43:41.847 [main] INFO c.e.d.s.a.i.l.MyBeanPostProcessor - postProcessBeforeInitialization, bean:smartLifecycle
541 2020-07-26 23:43:41.847 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - SMART_LIFECYCLE, postConstruct
541 2020-07-26 23:43:41.847 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - SMART_LIFECYCLE, afterPropertiesSet
541 2020-07-26 23:43:41.847 [main] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - SMART_LIFECYCLE, initMethod
541 2020-07-26 23:43:41.847 [main] INFO c.e.d.s.a.i.l.MyBeanPostProcessor - postProcessAfterInitialization, bean:smartLifecycle
550 2020-07-26 23:43:41.856 [main] INFO c.e.d.s.a.i.l.SmartLifecycleBean - start
5562 2020-07-26 23:43:46.868 [main] INFO c.e.d.s.a.ioc.lifecycle.Main - line ----------------------------- line
5563 2020-07-26 23:43:46.869 [main] INFO c.e.d.s.a.i.lifecycle.LifecycleBean - start
5566 2020-07-26 23:43:46.872 [main] INFO c.e.d.s.a.i.l.SmartLifecycleBean - stop
5566 2020-07-26 23:43:46.872 [main] INFO c.e.d.s.a.i.lifecycle.LifecycleBean - stop
5566 2020-07-26 23:43:46.872 [main] INFO c.e.d.s.a.ioc.lifecycle.Main - line ----------------------------- line
5576 2020-07-26 23:43:46.882 [SpringContextShutdownHook] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - SMART_LIFECYCLE, preDestroy
5576 2020-07-26 23:43:46.882 [SpringContextShutdownHook] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - SMART_LIFECYCLE, destroy
5576 2020-07-26 23:43:46.882 [SpringContextShutdownHook] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - SMART_LIFECYCLE, destroyMethod
5576 2020-07-26 23:43:46.882 [SpringContextShutdownHook] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - LIFECYCLE, preDestroy
5576 2020-07-26 23:43:46.882 [SpringContextShutdownHook] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - LIFECYCLE, destroy
5577 2020-07-26 23:43:46.883 [SpringContextShutdownHook] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - LIFECYCLE, destroyMethod
5577 2020-07-26 23:43:46.883 [SpringContextShutdownHook] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - NORMAL, preDestroy
5577 2020-07-26 23:43:46.883 [SpringContextShutdownHook] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - NORMAL, destroy
5577 2020-07-26 23:43:46.883 [SpringContextShutdownHook] INFO c.e.d.s.a.ioc.lifecycle.NormalBean - NORMAL, destroyMethod