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:
本章概要
- 本章由以下几部分组成:
- SmartLifecycle接口概览;
- spring容器启动与SmartLifecycle的关系;
- spring容器关闭与SmartLifecycle的关系;
- 关于Lifecycle和SmartLifecycle;
- 实战SmartLifecycle接口扩展;
SmartLifecycle接口概览
-
先来看看SmartLifecycle接口的类图:
- 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:
- 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:
- Lifecycle的处理都是委托给LifecycleProcessor执行的,先准备好此实例;
- 将所有的Lifecycle实例按照phase分组;
- 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:
-
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:
- 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;
- 将所有的Lifecycle实例按照phase分组;
- 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;
- 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;
- 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:
- 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 14:43:11.099 INFO 8008 --- [ main] o.s.j.e.a.AnnotationMBeanExporter : Registering beans for JMX exposure on startup
2018-08-26 14:43:11.102 INFO 8008 --- [ main] o.s.c.support.DefaultLifecycleProcessor : Starting beans in phase 666
2018-08-26 14:43:11.104 INFO 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 14:43:11.122 INFO 8008 --- [ main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2018-08-26 14:43:11.125 INFO 8008 --- [ main] c.b.c.CustomizelifecycleApplication : Started CustomizelifecycleApplication in 1.325 seconds (JVM running for 2.096)
-
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:
- 关闭日志如下所示:
2018-08-26 14:49:47.306 INFO 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 14:49:47.307 INFO 8008 --- [ Thread-6] o.s.c.support.DefaultLifecycleProcessor : Stopping beans in phase 666
2018-08-26 14:49:47.309 INFO 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 14:49:47.310 INFO 8008 --- [ Thread-6] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
Process finished with exit code 1
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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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