spring4.1.8扩展实战之四(感知spring容器变化(SmartLifecycle接口))

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本篇概览

  • 本章是《spring4.1.8扩展实战》的第四篇,如果业务上需要在spring容器启动和关闭的时候做一些操作,可以自定义SmartLifecycle接口的实现类来扩展,本章我们通过先分析再实战的方法,来掌握这种扩展方式;
往期扩展链接
前面三章已经做了一些扩展,地址如下:
  1. 《spring4.1.8扩展实战之一:自定义环境变量验证》;
  2. 《spring4.1.8扩展实战之二:Aware接口揭秘》;
  3. 《spring4.1.8扩展实战之三:广播与监听》;
本章概要
  • 本章由以下几部分组成:
    1. SmartLifecycle接口概览;
    2. spring容器启动与SmartLifecycle的关系;
    3. spring容器关闭与SmartLifecycle的关系;
    4. 关于Lifecycle和SmartLifecycle;
    5. 实战SmartLifecycle接口扩展;
SmartLifecycle接口概览
  • 先来看看SmartLifecycle接口的类图:
    spring4.1.8扩展实战之四(感知spring容器变化(SmartLifecycle接口))

    文章图片

  • 如上图所示,在继承了Lifecycle和Phased两个接口后,SmartLifecycle一共定义了六个方法,为了便于后面的源码分析,先做个简介:
方法 作用
start() bean初始化完毕后,该方法会被执行
stop() 容器关闭后:< br> spring容器发现当前对象实现了SmartLifecycle,就调用stop(Runnable),< br> 如果只是实现了Lifecycle,就调用stop()
isRunning() 当前状态
getPhase() 返回值决定start方法在众多Lifecycle实现类中的执行顺序(stop也是)
isAutoStartup() start方法被执行前先看此方法返回值,返回false就不执行start方法了
stop(Runnable) 容器关闭后:< br> spring容器发现当前对象实现了SmartLifecycle,就调用stop(Runnable),< br> 如果只是实现了Lifecycle,就调用stop()
  • 从上述列举中可以看出,感知容器变化的能力最终来自Lifecycle,而SmartLifecycle只是Lifecycle的增强版,可以自定义优先级(getPhase),自主决定是否随容器启动(isAutoStartup),以及停止时能接受一个runnable对象(stop(Runnable));
spring容器启动与SmartLifecycle的关系
  • 现在可以结合spring源码来看看SmartLifecycle的使用场景,从spring容器初始化看起;
  • AbstractApplicationContext类的refresh方法中,在bean的实例化和初始化操作完毕后,会调用finishRefresh方法,如下图红框所示:
spring4.1.8扩展实战之四(感知spring容器变化(SmartLifecycle接口))

文章图片

  • finishRefresh方法内容如下,中文注释对每个方法做了简介:
protected void finishRefresh() // LifecycleProcessor实例初始化, // LifecycleProcessor是所有Lifecycle实现类的管家,里面包含了对Lifecycle的各种操作. initLifecycleProcessor(); // 通过LifecycleProcessor来执行Lifecycle实现类的start方法 getLifecycleProcessor().onRefresh(); // 向监听器发送广播,消息类型是ContextRefreshedEvent publishEvent(new ContextRefreshedEvent(this)); // 如果配置了MBeanServer,就完成在MBeanServer上的注册 LiveBeansView.registerApplicationContext(this);

  • 上述代码中,initLifecycleProcessor()和getLifecycleProcessor().onRefresh()这两个方法和本章的主题有关,其他两个就不在本章展开了,我们从initLifecycleProcessor开始看起吧;
  • initLifecycleProcessor方法的作用是为applicationContext的成员变量lifecycleProcessor赋值,如果已有名为" lifecycleProcessor" 的bean,lifecycleProcessor就等于这个bean,否则就实例化一个DefaultLifecycleProcessor对象,再让lifecycleProcessor等于这个对象,并且把这个对象作注册到spring环境中(名为" lifecycleProcessor" ),源码如下:
protected void initLifecycleProcessor() ConfigurableListableBeanFactory beanFactory = getBeanFactory(); if (beanFactory.containsLocalBean(LIFECYCLE_PROCESSOR_BEAN_NAME)) this.lifecycleProcessor = beanFactory.getBean(LIFECYCLE_PROCESSOR_BEAN_NAME, LifecycleProcessor.class); if (logger.isDebugEnabled()) logger.debug("Using LifecycleProcessor [" + this.lifecycleProcessor + "]"); else DefaultLifecycleProcessor defaultProcessor = new DefaultLifecycleProcessor(); defaultProcessor.setBeanFactory(beanFactory); this.lifecycleProcessor = defaultProcessor; beanFactory.registerSingleton(LIFECYCLE_PROCESSOR_BEAN_NAME, this.lifecycleProcessor); if (logger.isDebugEnabled()) logger.debug("Unable to locate LifecycleProcessor with name " + LIFECYCLE_PROCESSOR_BEAN_NAME + ": using default [" + this.lifecycleProcessor + "]");

  • 接下来是==getLifecycleProcessor().onRefresh()==的执行,如果业务不自定义一个LifecycleProcessor,就默认创建一个DefaultLifecycleProcessor对象,因此执行的就是DefaultLifecycleProcessor的onRefresh方法,来看看源码:
@Override public void onRefresh() startBeans(true); this.running = true;

  • 展开startBeans方法看看,==注意入参autoStartupOnly等于true==:
private void startBeans(boolean autoStartupOnly) //取得所有Lifecycle接口的实例,此map的key是实例的名称,value是实例 Map< String, Lifecycle> lifecycleBeans = getLifecycleBeans(); Map< Integer, LifecycleGroup> phases = new HashMap< Integer, LifecycleGroup> (); for (Map.Entry< String, ? extends Lifecycle> entry : lifecycleBeans.entrySet()) Lifecycle bean = entry.getValue(); //autoStartupOnly等于true时,bean必须实现SmartLifecycle接口,并且isAutoStartup()返回true,才会被放入LifecycleGroup中(后续会从LifecycleGroup中取出来执行start()) if (!autoStartupOnly || (bean instanceof SmartLifecycle & & ((SmartLifecycle) bean).isAutoStartup())) int phase = getPhase(bean); LifecycleGroup group = phases.get(phase); if (group == null) group = new LifecycleGroup(phase, this.timeoutPerShutdownPhase, lifecycleBeans, autoStartupOnly); //phases是个map,key是Lifecycle实例的phase值,value是Lifecycle实例 phases.put(phase, group); //当前实例加入LifecycleGroup中,该LifecycleGroup内的所有实例的phase都相等 group.add(entry.getKey(), bean); if (phases.size() > 0) List< Integer> keys = new ArrayList< Integer> (phases.keySet()); //按照所有的phase值排序,然后依次执行bean的start方法,每次都是一批phase相同的 Collections.sort(keys); for (Integer key : keys) //这里面会对所有Lifecycle实例逐个调用start方法 phases.get(key).start();

  • SmartLifecycle的实例的start被调用的地方是在LifecycleGroup内部,对应的方法是doStart,如下所示,优先处理依赖bean:
private void doStart(Map< String, ? extends Lifecycle> lifecycleBeans, String beanName, boolean autoStartupOnly) Lifecycle bean = lifecycleBeans.remove(beanName); if (bean != null & & !this.equals(bean)) String[] dependenciesForBean = this.beanFactory.getDependenciesForBean(beanName); for (String dependency : dependenciesForBean) //如果有依赖类,就先调用依赖类的start方法,这里做了迭代调用 doStart(lifecycleBeans, dependency, autoStartupOnly); //条件略多,首先要求isRunning返回false,其次:不能是SmartLifecycle的实现类,若是SmartLifecycle实现类,其isAutoStartup方法必须返回true if (!bean.isRunning() & & (!autoStartupOnly || !(bean instanceof SmartLifecycle) || ((SmartLifecycle) bean).isAutoStartup())) if (logger.isDebugEnabled()) logger.debug("Starting bean " + beanName + " of type [" + bean.getClass() + "]"); try bean.start(); catch (Throwable ex) throw new ApplicationContextException("Failed to start bean " + beanName + "", ex); if (logger.isDebugEnabled()) logger.debug("Successfully started bean " + beanName + "");

  • 以上就是初始化阶段容器对SmartLifecycle实例的处理逻辑,简单的小结如下:
    1. Lifecycle的处理都是委托给LifecycleProcessor执行的,先准备好此实例;
    2. 将所有的Lifecycle实例按照phase分组;
    3. 从phase值最小的分组开始,依次执行其中每个Lifecycle对象的start方法;
  • 关于容器启动时的Lifecycle的处理就分析到这里,接下来看看容器关闭时对Lifecycle操作;
spring容器关闭与SmartLifecycle的关系
  • 分析SmartLifecycle如何感知spring容器的关闭,首先要弄清楚stop方法的调用栈,从LifecycleProcessor接口看起吧:
public interface LifecycleProcessor extends Lifecycle /** * Notification of context refresh, e.g. for auto-starting components. */ void onRefresh(); /** * Notification of context close phase, e.g. for auto-stopping components. */ void onClose();

  • 如上所示,感知容器关闭只能靠onClose方法被调用了,去看看该方法的调用处;< br>
  • LifecycleProcessor的onClose方法是在AbstractApplicationContext的doClose方法中被调用的,如下图红框所示,这是汇集了容器关闭时要执行的基本逻辑:
spring4.1.8扩展实战之四(感知spring容器变化(SmartLifecycle接口))

文章图片

  • 弄清了调用逻辑,可以去DefaultLifecycleProcessor中看看SmartLifecycle实例的stop方法是如何被调用的;
  • DefaultLifecycleProcessor的stop方法中先调用stopBeans方法,再将成员变量running设置为false,表示状态已不是运行中:
@Override public void stop() stopBeans(); this.running = false;

  • 展开stopBeans方法:
private void stopBeans() //取得所有Lifecycle接口的实例,此map的key是实例的名称,value是实例 Map< String, Lifecycle> lifecycleBeans = getLifecycleBeans(); Map< Integer, LifecycleGroup> phases = new HashMap< Integer, LifecycleGroup> (); for (Map.Entry< String, Lifecycle> entry : lifecycleBeans.entrySet()) Lifecycle bean = entry.getValue(); //SmartLifecycle实例通过getPhase方法返回,只实现了Lifecycle的返回0 int shutdownOrder = getPhase(bean); LifecycleGroup group = phases.get(shutdownOrder); if (group == null) group = new LifecycleGroup(shutdownOrder, this.timeoutPerShutdownPhase, lifecycleBeans, false); //phases是个map,key是Lifecycle实例的phase值,value是Lifecycle实例 phases.put(shutdownOrder, group); group.add(entry.getKey(), bean); if (phases.size() > 0) List< Integer> keys = new ArrayList< Integer> (phases.keySet()); //按照phase排序,和启动的时候的排序正好相反 Collections.sort(keys, Collections.reverseOrder()); for (Integer key : keys) //对phase相同的Lifecycle实例,逐一执行stop方法 phases.get(key).stop();

  • 上述代码和启动时执行start的逻辑基本相似,不同的是执行顺序正好相反;
  • 看看LifecycleGroup的stop方法内部,是如何调用Lifecycle实例的stop方法的:
public void stop() if (this.members.isEmpty()) return; if (logger.isInfoEnabled()) logger.info("Stopping beans in phase " + this.phase); Collections.sort(this.members, Collections.reverseOrder()); //这里有个同步逻辑,CounDownLatch中计数器的数量为当前LifecycleGroup中Lifecycle实例数量 CountDownLatch latch = new CountDownLatch(this.smartMemberCount); Set< String> countDownBeanNames = Collections.synchronizedSet(new LinkedHashSet< String> ()); for (LifecycleGroupMember member : this.members) //这个containsKey判断很重要,在doStop方法中,SmartLifecycle的stop方法可能会在新线程中执行,执行时如果发现了bean的依赖bean,会先去执行依赖bean的stop方法, //因此有可能此处的Lifecycle实例是实例A的依赖bean,已经在执行A实例的stop时执行过stop方法了,执行stop方法完成的时候会将自己从this.lifecycleBeans中remove掉,所以在this.lifecycleBeans就不存在了 if (this.lifecycleBeans.containsKey(member.name)) doStop(this.lifecycleBeans, member.name, latch, countDownBeanNames); else if (member.bean instanceof SmartLifecycle) latch.countDown(); try //等到所有Lifecycle实例都执行完毕,当前线程才会执行下去 latch.await(this.timeout, TimeUnit.MILLISECONDS); if (latch.getCount() > 0 & & !countDownBeanNames.isEmpty() & & logger.isWarnEnabled()) logger.warn("Failed to shut down " + countDownBeanNames.size() + " bean" + (countDownBeanNames.size() > 1 ? "s" : "") + " with phase value " + this.phase + " within timeout of " + this.timeout + ": " + countDownBeanNames); catch (InterruptedException ex) Thread.currentThread().interrupt();

  • 以上代码有一处需要注意:
  • SmartLifecycle实例有个stop(Runnable)方法,实现的时候可以在另一个线程中执行stop的逻辑,这样就可以多个SmartLifecycle实例并行执行stop逻辑了,可以提高执行速度,当前线程为了等待所有执行stop的线程,用了CountDownLatch来等待,为了避免无限期等待还设置了超时时间;
  • 最后来看看LifecycleGroup的stop方法中循环调用的doStop方法吧,这里面才会真正的调用到Lifecycle实例的stop方法,还有上面我们分析的多线程逻辑:
private void doStop(Map< String, ? extends Lifecycle> lifecycleBeans, final String beanName, final CountDownLatch latch, final Set< String> countDownBeanNames) //从成员变量lifecycleBeans中remove当前bean,表示已经执行过stop方法 Lifecycle bean = lifecycleBeans.remove(beanName); if (bean != null) //找出依赖bean,通过迭代调用来保证依赖bean先执行stop方法 String[] dependentBeans = this.beanFactory.getDependentBeans(beanName); for (String dependentBean : dependentBeans) //迭代 doStop(lifecycleBeans, dependentBean, latch, countDownBeanNames); try //isRunning方法返回true才会执行stop,因此自定义Lifecycle的时候要注意 if (bean.isRunning()) if (bean instanceof SmartLifecycle) if (logger.isDebugEnabled()) logger.debug("Asking bean " + beanName + " of type [" + bean.getClass() + "] to stop"); countDownBeanNames.add(beanName); //传入CountDownLatch减一的逻辑,这样SmartLifecycle的stop方法中就可以使用新线程来执行相关逻辑了,记得执行完毕后再执行Runnable中的逻辑,这样主线程才不会一直等待; ((SmartLifecycle) bean).stop(new Runnable() @Override public void run() latch.countDown(); countDownBeanNames.remove(beanName); if (logger.isDebugEnabled()) logger.debug("Bean " + beanName + " completed its stop procedure"); ); else if (logger.isDebugEnabled()) logger.debug("Stopping bean " + beanName + " of type [" + bean.getClass() + "]"); //如果不是SmartLifecycle实例,就调用stop,在当前线程中执行 bean.stop(); if (logger.isDebugEnabled()) logger.debug("Successfully stopped bean " + beanName + ""); else if (bean instanceof SmartLifecycle) // CountDownLatch中计数器的数量是按照SmartLifecycle实例的数量来算的,如果不在runing状态,实例的stop方法就不会调用,主线程就不用等待这次stop,latch直接减一 latch.countDown(); catch (Throwable ex) if (logger.isWarnEnabled()) logger.warn("Failed to stop bean " + beanName + "", ex);

  • 从以上代码可以看出,SmartLifecycle实现类的stop(Runnable)被调用时,LifecycleGroup已经将stop调用完毕后要做的工作通过Runnable传递给实现类了,因此实现类中要记得执行Runnable的run方法,否则会导致外部调用逻辑的参数不准备,影响调用线程的执行;
  • 以上就是关闭容器阶段对SmartLifecycle实例的处理逻辑,简单的小结如下:
    1. AbstractApplicationContext的doClose方法在容器关闭时会被执行,此处调用LifecycleProcessor的onClose方法,由LifecycleProcessor负责所有Lifecycle实例的关闭操作;
    2. 将所有的Lifecycle实例按照phase分组;
    3. 从phase值最大的分组开始,依次执行其中每个Lifecycle对象的stop方法;
    4. 对每个SmartLifecycle实例,若想并行执行以加快stop执行速度,可以在stop方法中用新的线程来执行stop业务逻辑,但是最后不要忘记调用Runnable入参的run方法,以完成主线程的计数和统计;
    5. 主线程使用了CountDownLatch,在调用了SmartLifecycle实例的stop方法后就会等待,等到计数达到SmartLifecycle总数或者等待超时,再继续向后执行;
  • 关于容器启动时的Lifecycle的处理就分析到这里,接下来看看容器关闭时对Lifecycle操作;
Lifecycle和SmartLifecycle,自定义的时候用哪个?
  • 看了上面的源码分析,我们对Lifecycle和SmartLifecycle有了更全面的认知,如果对执行顺序没有要求,在关闭的时候也没有性能或者时间要求,那么就用Lifecycle吧,因为更简单,如果在乎顺序,也期望关闭时多个Lifecycle实例能并行执行,快速结束,SmartLifecycle无疑更适合;
  • 理论上已经基本熟悉了,接下来通过一次实战来加深印象,我们自定义一个SmartLifecycle的实现类,并在springboot中验证以下;
实战SmartLifecycle接口扩展
  • 本次实战的内容是创建一个springboot工程,在里面自定义一个SmartLifecycle接口的实现类,如果您不想敲代码,也可以去github下载源码,地址和链接信息如下表所示:
名称 链接 备注
项目主页 https://github.com/zq2599/blog_demos 该项目在GitHub上的主页
git仓库地址(https) https://github.com/zq2599/blog_demos.git 该项目源码的仓库地址,https协议
git仓库地址(ssh) git@github.com:zq2599/blog_demos.git 该项目源码的仓库地址,ssh协议
  • 这个git项目中有多个文件夹,本章源码在文件夹customizelifecycle下,如下图红框所示:
spring4.1.8扩展实战之四(感知spring容器变化(SmartLifecycle接口))

文章图片

  • 接下来开始实战吧:
  • 基于maven创建一个springboot的web工程,名为customizelifecycle,pom.xml如下:
< ?xml version="1.0" encoding="UTF-8"?> < project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> < modelVersion> 4.0.0< /modelVersion> < groupId> com.bolingcavalry< /groupId> < artifactId> customizelifecycle< /artifactId> < version> 0.0.1-SNAPSHOT< /version> < packaging> jar< /packaging> < name> customizelifecycle< /name> < description> Demo project for Spring Boot< /description> < parent> < groupId> org.springframework.boot< /groupId> < artifactId> spring-boot-starter-parent< /artifactId> < version> 1.5.15.RELEASE< /version> < relativePath/> < !-- lookup parent from repository --> < /parent> < properties> < project.build.sourceEncoding> UTF-8< /project.build.sourceEncoding> < project.reporting.outputEncoding> UTF-8< /project.reporting.outputEncoding> < java.version> 1.8< /java.version> < /properties> < dependencies> < dependency> < groupId> org.springframework.boot< /groupId> < artifactId> spring-boot-starter-web< /artifactId> < /dependency> < dependency> < groupId> org.springframework.boot< /groupId> < artifactId> spring-boot-starter-test< /artifactId> < scope> test< /scope> < /dependency> < /dependencies> < build> < plugins> < plugin> < groupId> org.springframework.boot< /groupId> < artifactId> spring-boot-maven-plugin< /artifactId> < /plugin> < /plugins> < /build> < /project>

  • 创建Utils.java,里面提供常用的静态方法,本次会用到的是printTrack方法,用来打印当前堆栈,便于我们观察程序执行情况:
package com.bolingcavalry.customizelifecycle.util; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * @Description : 提供一些常用的工具方法 * @Author : zq2599@gmail.com * @Date : 2018-08-14 05:51 */ public class Utils private static final Logger logger = LoggerFactory.getLogger(Utils.class); /** * 打印当前线程堆栈信息 * @param prefix */ public static void printTrack(String prefix) StackTraceElement[] st = Thread.currentThread().getStackTrace(); if(null==st) logger.info("invalid stack"); return; StringBuffer sbf =new StringBuffer(); for(StackTraceElement e:st) if(sbf.length()> 0) sbf.append(" < - "); sbf.append(System.getProperty("line.separator")); sbf.append(java.text.MessageFormat.format("0.1() 2" ,e.getClassName() ,e.getMethodName() ,e.getLineNumber())); logger.info(prefix + "\\n************************************************************\\n" + sbf.toString() + "\\n************************************************************");

  • 创建自定义SmartLifecycle实现类CustomizeLifeCycleLinstener.java,主要代码都有注释说明,就不多赘述了,前面咱们分析的几个调用方法都有日志打印,便于在执行的时候观察,另外需要注意的是stop(Runnable)方法的实现中用了一个新的线程来执行关闭的逻辑,并且入参Runnable的run方法一定要调用:
package com.bolingcavalry.customizelifecycle.lifecycle; import com.bolingcavalry.customizelifecycle.util.Utils; import org.springframework.context.SmartLifecycle; import org.springframework.stereotype.Component; /** * @Description : SmartLifecycle的实现类,在spring容器初始化完毕和关闭的时候被spring容器回调,完成特定的业务需求 * @Author : zq2599@gmail.com * @Date : 2018-08-25 13:59 */ @Component public class CustomizeLifeCycleLinstener implements SmartLifecycle public boolean isRunningFlag() return runningFlag; public void setRunningFlag(boolean runningFlag) this.runningFlag = runningFlag; private boolean runningFlag = false; @Override public void stop(Runnable callback) new Thread(new Runnable() @Override public void run() Utils.printTrack("do stop with callback param"); //设置为false,表示已经不在执行中了 setRunningFlag(false); //callback中有个CountDownLatch实例,总数是SmartLifecycle对象的数量, //此方法被回调时CountDownLatch实例才会减一,初始化容器的线程一直在wait中; callback.run(); ).start(); @Override public void start() Utils.printTrack("do start"); //设置为false,表示正在执行中 setRunningFlag(true); @Override public void stop() Utils.printTrack("do stop"); //设置为false,表示已经不在执行中了 setRunningFlag(false); @Override public int getPhase() return 666; @Override public boolean isRunning() return isRunningFlag(); @Override public boolean isAutoStartup() //只有设置为true,start方法才会被回调 return true;

  • 启动类CustomizelifecycleApplication.java如下:
package com.bolingcavalry.customizelifecycle; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class CustomizelifecycleApplication public static void main(String[] args) SpringApplication.run(CustomizelifecycleApplication.class, args);

  • 编码完毕,启动应用,日志如下(篇幅所限,前面那段springboot启动的常见日志去掉了):
2018-08-26 14:43:11.099INFO 8008 --- [main] o.s.j.e.a.AnnotationMBeanExporter: Registering beans for JMX exposure on startup 2018-08-26 14:43:11.102INFO 8008 --- [main] o.s.c.support.DefaultLifecycleProcessor: Starting beans in phase 666 2018-08-26 14:43:11.104INFO 8008 --- [main] c.b.customizelifecycle.util.Utils: do start ************************************************************ java.lang.Thread.getStackTrace() 1,559 < - com.bolingcavalry.customizelifecycle.util.Utils.printTrack() 20 < - com.bolingcavalry.customizelifecycle.lifecycle.CustomizeLifeCycleLinstener.start() 45 < - org.springframework.context.support.DefaultLifecycleProcessor.doStart() 173 < - org.springframework.context.support.DefaultLifecycleProcessor.access$200() 50 < - org.springframework.context.support.DefaultLifecycleProcessor$LifecycleGroup.start() 346 < - org.springframework.context.support.DefaultLifecycleProcessor.startBeans() 149 < - org.springframework.context.support.DefaultLifecycleProcessor.onRefresh() 112 < - org.springframework.context.support.AbstractApplicationContext.finishRefresh() 880 < - org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh() 144 < - org.springframework.context.support.AbstractApplicationContext.refresh() 546 < - org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh() 122 < - org.springframework.boot.SpringApplication.refresh() 693 < - org.springframework.boot.SpringApplication.refreshContext() 360 < - org.springframework.boot.SpringApplication.run() 303 < - org.springframework.boot.SpringApplication.run() 1,118 < - org.springframework.boot.SpringApplication.run() 1,107 < - com.bolingcavalry.customizelifecycle.CustomizelifecycleApplication.main() 10 ************************************************************ 2018-08-26 14:43:11.122INFO 8008 --- [main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http) 2018-08-26 14:43:11.125INFO 8008 --- [main] c.b.c.CustomizelifecycleApplication: Started CustomizelifecycleApplication in 1.325 seconds (JVM running for 2.096)

  • 【spring4.1.8扩展实战之四(感知spring容器变化(SmartLifecycle接口))】上述日志可以看到CustomizeLifeCycleLinstener的日志输出和执行堆栈,与预期一致;
  • 接下来验证关闭的逻辑了,有两种方式可以验证,第一种是将当前的应用做成jar包运行,在控制台输入" CTRL+C" 即可触发容器关闭,还有一种更简单的,如果您用的是IDEA开发,那么请用IDEA将应用启动,关闭的时候点击下图红框中的按钮,即可触发容器关闭:
    spring4.1.8扩展实战之四(感知spring容器变化(SmartLifecycle接口))

    文章图片

  • 关闭日志如下所示:
2018-08-26 14:49:47.306INFO 8008 --- [Thread-6] ationConfigEmbeddedWebApplicationContext : Closing org.springframework.boot.context.embedded.AnnotationConfigEmbeddedWebApplicationContext@27c6e487: startup date [Sun Aug 26 14:43:10 GMT+08:00 2018]; root of context hierarchy 2018-08-26 14:49:47.307INFO 8008 --- [Thread-6] o.s.c.support.DefaultLifecycleProcessor: Stopping beans in phase 666 2018-08-26 14:49:47.309INFO 8008 --- [Thread-11] c.b.customizelifecycle.util.Utils: do stop with callback param ************************************************************ java.lang.Thread.getStackTrace() 1,559 < - com.bolingcavalry.customizelifecycle.util.Utils.printTrack() 20 < - com.bolingcavalry.customizelifecycle.lifecycle.CustomizeLifeCycleLinstener$1.run() 32 < - java.lang.Thread.run() 748 ************************************************************ 2018-08-26 14:49:47.310INFO 8008 --- [Thread-6] o.s.j.e.a.AnnotationMBeanExporter: Unregistering JMX-exposed beans on shutdownProcess finished with exit code 1

  • 如上述日志所示,由于CustomizeLifeCycleLinstener的stop方法中新建了一个线程来执行操作,因此日志中的堆栈是这个新线程的堆栈信息,如果您想看到主线程的调用堆栈,请去掉new Thread的代码再次运行即可;
  • 至此,SmartLifecycle接口的源码分析和自定义实战就全部结束了,对spring强大的扩展能力又多了一分认识,真心希望本文能助您在感知容器变化的开发中收获一些启发,当然,spring中还有更多精彩的扩展等着我们去探索,下一篇咱们继续;
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