spring4.1.8扩展实战之三:广播与监听

本文涉及的产品
日志服务 SLS,月写入数据量 50GB 1个月
简介: 提到广播与监听,我们常常会想到RabbitMQ、Kafka等消息中间件,这些常用于分布式系统中多个应用之间,有时候应用自身内部也有广播和监听的需求(例如某个核心数据发生变化后,有些业务模块希望立即被感知),这时候spring提供的基于ApplicationContext的广播与监听就派上用场了,接下来我们从原理到实践,来了解spring提供的这套机制吧

欢迎访问我的GitHub

这里分类和汇总了欣宸的全部原创(含配套源码): https://github.com/zq2599/blog_demos
  • 提到广播与监听,我们常常会想到RabbitMQ、Kafka等消息中间件,这些常用于分布式系统中多个应用之间,有时候应用自身内部也有广播和监听的需求(例如某个核心数据发生变化后,有些业务模块希望立即被感知),这时候spring提供的基于ApplicationContext的广播与监听就派上用场了,接下来我们从原理到实践,来了解spring提供的这套机制吧。

全文概览

  • 总的来说本章内容由以下部分构成:
  1. 学习广播服务的核心接口;
  2. spring的容器内广播和监听的源码查看;
  3. spring是如何支持自定义广播的;
  4. spring是如何支持自定义监听的;
  5. 开发一个自定义广播;
  6. 开发一个自定义监听;

ApplicationEventPublisher:广播服务的核心能力

  • 提到spring容器中的广播和监听,就不得不先看看ApplicationEventPublisher这个接口,今天的故事都是围绕此君展开:
@FunctionalInterface
public interface ApplicationEventPublisher {

    /**
     * Notify all <strong>matching</strong> listeners registered with this
     * application of an application event. Events may be framework events
     * (such as RequestHandledEvent) or application-specific events.
     * @param event the event to publish
     * @see org.springframework.web.context.support.RequestHandledEvent
     */
    default void publishEvent(ApplicationEvent event) {
        publishEvent((Object) event);
    }

    /**
     * Notify all <strong>matching</strong> listeners registered with this
     * application of an event.
     * <p>If the specified {@code event} is not an {@link ApplicationEvent},
     * it is wrapped in a {@link PayloadApplicationEvent}.
     * @param event the event to publish
     * @since 4.2
     * @see PayloadApplicationEvent
     */
    void publishEvent(Object event);

}
  • 从上述代码可以看出,发送消息实际上就是在调用ApplicationEventPublisher 接口实现类的publishEvent方法,接下来看看类图,了解在spring容器的设计中ApplicationEventPublisher的定位:

image.png

  • 从上图可见,ApplicationContext继承了ApplicationEventPublisher,那么ApplicationContext的实现类自然也就具备了发送广播的能力,按照这个思路去看一下关键的抽象类AbstractApplicationContext,果然找到了方法实现:
@Override
public void publishEvent(ApplicationEvent event) {
    publishEvent(event, null);
}

如何广播一条消息

  • 来看一个具体的广播的例子吧,spring容器初始化结束的时候,会执行AbstractApplicationContext类的finishRefresh方法,里面就会广播一条代表初始化结束的消息,代码如下:
protected void finishRefresh() {
    // Clear context-level resource caches (such as ASM metadata from scanning).
    clearResourceCaches();

    // Initialize lifecycle processor for this context.
    initLifecycleProcessor();

    // Propagate refresh to lifecycle processor first.
    getLifecycleProcessor().onRefresh();

    // 广播一条消息,类型ContextRefreshedEvent代表spring容器初始化结束
    publishEvent(new ContextRefreshedEvent(this));

    // Participate in LiveBeansView MBean, if active.
    LiveBeansView.registerApplicationContext(this);
}
  • 继续深入publichEvent方法内部,看到的代码如下图所示:

image.png

  • 上图中的绿色部分的判断不成立,初始化过程中的registerListeners方法就会把成员变量earlyApplicationEvents设置为空,因此广播消息执行的是getApplicationEventMulticaster().multicastEvent(applicationEvent, eventType),在ApplicationContext的实现类中,真正的广播操作交给了成员变量applicationEventMulticaster来完成,没有特殊配置的话,applicationEventMulticaster是SimpleApplicationEventMulticaster类型的实例(详情请看initApplicationEventMulticaster方法);
  • 打开的源码,如下所示,是否有种豁然开朗的感觉?广播的实现是如此简单明了,找到已注册的ApplicationListener,逐个调用invokeListener方法,将ApplicationListener和事件作为入参传进去就完成了广播;
@Override
    public void multicastEvent(final ApplicationEvent event, @Nullable ResolvableType eventType) {
        ResolvableType type = (eventType != null ? eventType : resolveDefaultEventType(event));
        for (final ApplicationListener<?> listener : getApplicationListeners(event, type)) {
            Executor executor = getTaskExecutor();
            if (executor != null) {
                executor.execute(() -> invokeListener(listener, event));
            }
            else {
                invokeListener(listener, event);
            }
        }
    }
  • 看到这里,invokeListener方法所做的事情已经很容易猜到了,ApplicationListener是代表监听的接口,只要调用这个接口的方法并且将event作为入参传进去,那么每个监听器就可以按需要自己来处理这条广播消息了,看了代码发现我们的猜测是正确的:
private void doInvokeListener(ApplicationListener listener, ApplicationEvent event) {
        try {
            //这里就是监听器收到广播时做的事情
            listener.onApplicationEvent(event);
        }
        catch (ClassCastException ex) {
            String msg = ex.getMessage();
            if (msg == null || matchesClassCastMessage(msg, event.getClass().getName())) {
                // Possibly a lambda-defined listener which we could not resolve the generic event type for
                // -> let's suppress the exception and just log a debug message.
                Log logger = LogFactory.getLog(getClass());
                if (logger.isDebugEnabled()) {
                    logger.debug("Non-matching event type for listener: " + listener, ex);
                }
            }
            else {
                throw ex;
            }
        }
    }
  • 另外还有个细节需要补充,这是在后面做自定义广播的时候考虑到的:如果多线程同时发广播,会不会有线程同步的问题?发送广播的源码一路看下来,发现操作全部在发送的线程中执行的,对各种成员变量的操作也没有出现线程同步问题,唯一有可能出现问题的地方在获取ApplicationListener的时候,这里用到了缓存,有缓存更新的逻辑,而spring已经做好了锁来确保线程同步(双重判断也做了),来看看源码,注意中文注释:
protected Collection<ApplicationListener<?>> getApplicationListeners(
            ApplicationEvent event, ResolvableType eventType) {

        Object source = event.getSource();
        Class<?> sourceType = (source != null ? source.getClass() : null);
        ListenerCacheKey cacheKey = new ListenerCacheKey(eventType, sourceType);

        //retrieverCache是个ConcurrentHashMap
        ListenerRetriever retriever = this.retrieverCache.get(cacheKey);
        if (retriever != null) {
            return retriever.getApplicationListeners();
        }

        //如果没有从缓存中取到,就要获取了数据再返回
        if (this.beanClassLoader == null ||
                (ClassUtils.isCacheSafe(event.getClass(), this.beanClassLoader) &&
                        (sourceType == null || ClassUtils.isCacheSafe(sourceType, this.beanClassLoader)))) {
            // 这里有锁
            synchronized (this.retrievalMutex) {
                retriever = this.retrieverCache.get(cacheKey);
                //抢到锁之后再做一次判断,因为有可能在前面BLOCK的时候,另一个抢到锁的线程已经设置好了缓存
                if (retriever != null) {
                    return retriever.getApplicationListeners();
                }
                retriever = new ListenerRetriever(true);
                Collection<ApplicationListener<?>> listeners =
                        retrieveApplicationListeners(eventType, sourceType, retriever);
                this.retrieverCache.put(cacheKey, retriever);
                return listeners;
            }
        }
        else {
            // No ListenerRetriever caching -> no synchronization necessary
            return retrieveApplicationListeners(eventType, sourceType, null);
        }
    }
  • 看到这里,我们对spring容器内的广播与监听已经有所了解,小结如下:
  1. 广播的核心接口是ApplicationEventPublisher;
  2. 我们见过了如何发起一条广播,监听器如何响应广播;
  • 接下来还不能马上动手实战,我们还有两件事情要想弄清楚:
  1. 我想发自定义的广播消息,如何具备这个发送能力?
  2. 我想接收特定的广播,如何具备这个接收能力?
  • 接下来,继续结合spring源码去找上面两个问题的答案;

源码分析(如何具备消息发送能力)

  • 先看消息生产相关的源码,在上一章《spring4.1.8扩展实战之二:Aware接口揭秘》中,我们看到spring容器初始化的时候会对实现了Aware接口的bean做相关的特殊处理,其中就包含ApplicationEventPublisherAware这个与广播发送相关的接口,代码如下(ApplicationContextAwareProcessor.java):
private void invokeAwareInterfaces(Object bean) {
        if (bean instanceof Aware) {
            if (bean instanceof EnvironmentAware) {
                ((EnvironmentAware) bean).setEnvironment(this.applicationContext.getEnvironment());
            }
            if (bean instanceof EmbeddedValueResolverAware) {
                ((EmbeddedValueResolverAware) bean).setEmbeddedValueResolver(this.embeddedValueResolver);
            }
            if (bean instanceof ResourceLoaderAware) {
                ((ResourceLoaderAware) bean).setResourceLoader(this.applicationContext);
            }

            //如果想在应用内发送广播,需要开发一个实现了ApplicationEventPublisherAware接口的bean,就会在此被注入一个ApplicationEventPublisher对象,借助这个对象就能发送广播了
            if (bean instanceof ApplicationEventPublisherAware) {
                ((ApplicationEventPublisherAware) bean).setApplicationEventPublisher(this.applicationContext);
            }
            if (bean instanceof MessageSourceAware) {
                ((MessageSourceAware) bean).setMessageSource(this.applicationContext);
            }
            if (bean instanceof ApplicationContextAware) {
                ((ApplicationContextAware) bean).setApplicationContext(this.applicationContext);
            }
        }
    }
  • 由以上代码可见,我们可以创建一个bean,实现了ApplicationEventPublisherAware接口,那么该bean的setApplicationEventPublisher方法就会被调用,通过该方法可以接收到ApplicationEventPublisher类型的入参,借助这个ApplicationEventPublisher就可以发消息了;

源码分析(如何具备消息接收能力)

  • 在spring容器初始化的时候,AbstractApplicationContext类的prepareBeanFactory方法中为所有bean准备了一个后置处理器ApplicationListenerDetector,来看看它的postProcessAfterInitialization方法的代码,也就是bean在实例化之后要做的事情:
@Override
    public Object postProcessAfterInitialization(Object bean, String beanName) {
        if (bean instanceof ApplicationListener) {
            // potentially not detected as a listener by getBeanNamesForType retrieval
            Boolean flag = this.singletonNames.get(beanName);
            if (Boolean.TRUE.equals(flag)) {
                //注册监听器,其实就是保存在成员变量applicationEventMulticaster的成员变量defaultRetriever的集合applicationListeners中
                this.applicationContext.addApplicationListener((ApplicationListener<?>) bean);
            }
            else if (Boolean.FALSE.equals(flag)) {
                if (logger.isWarnEnabled() && !this.applicationContext.containsBean(beanName)) {
                    // inner bean with other scope - can't reliably process events
                    logger.warn("Inner bean '" + beanName + "' implements ApplicationListener interface " +
                            "but is not reachable for event multicasting by its containing ApplicationContext " +
                            "because it does not have singleton scope. Only top-level listener beans are allowed " +
                            "to be of non-singleton scope.");
                }
                this.singletonNames.remove(beanName);
            }
        }
        return bean;
    }
  • 如上所示,如果当前bean实现了ApplicationListener接口,就会调用this.applicationContext.addApplicationListener方法将当前bean注册到applicationContext的监听器集合中,后面有广播就直接找到这些监听器,调用每个监听器的onApplicationEvent方法;
  • 现在把广播与监听的关键代码都看过了,可以开始实战了么?稍等,还有最后一个疑问要弄明白:自定义的消息监听器可以指定消息类型,所有的广播消息中,这个监听器只会收到自己指定的消息类型的广播,spring是如何做到这一点的?

如何做到只接收指定类型的消息

  • 此问题的答案就在spring源码中,但是看源码之前先自己猜测一下,自定义监听器只接收指定类型的消息,以下两种方案都可以实现:
  1. 注册监听器的时候,将监听器和消息类型绑定;
  2. 广播的时候,按照这条消息的类型去找指定了该类型的监听器,但不可能每条广播都去所有监听器里面找一遍,应该是说广播的时候会触发一次监听器和消息的类型绑定;
  • 带着上述猜测去spring源码中寻找答案吧,先看注册监听器的代码,按照之前的分析,注册监听发生在后置处理器ApplicationListenerDetector中,看看this.applicationContext.addApplicationListener这一行代码的内部逻辑:
@Override
    public void addApplicationListener(ApplicationListener<?> listener) {
        Assert.notNull(listener, "ApplicationListener must not be null");
        if (this.applicationEventMulticaster != null) {
            this.applicationEventMulticaster.addApplicationListener(listener);
        }
        else {
            this.applicationListeners.add(listener);
        }
    }
  • 最终跟踪到AbstractApplicationEventMulticaster类的addApplicationListener方法:
@Override
public void addApplicationListener(ApplicationListener<?> listener) {
    synchronized (this.retrievalMutex) {
        // Explicitly remove target for a proxy, if registered already,
        // in order to avoid double invocations of the same listener.
        Object singletonTarget = AopProxyUtils.getSingletonTarget(listener);
        if (singletonTarget instanceof ApplicationListener) {
            //如果因为AOP导致创建了监听类的代理,那么就要在注册列表中清除代理类
            this.defaultRetriever.applicationListeners.remove(singletonTarget);
        }
        //把监听器加入集合defaultRetriever.applicationListeners中,这是个LinkedHashSet实例
        this.defaultRetriever.applicationListeners.add(listener);
        this.retrieverCache.clear();
    }
}
  • 从以上代码我们发现了两个关键点:
  • AOP是通过代理技术实现的,此时可能通过CGLIB生成了监听类的代理类,此类的实例如果也被注册到监听器集合中,那么广播的时候,按照消息类型就会取出两个监听器实例来了,到时候的效果就是一个消息被两个实例消费了,因此这里要先清理掉代理类;
  • 所谓的注册监听器,其实就是把ApplicationListener的实现类放入一个LinkedHashSet的集合,此处没有任何与消息类型相关的操作,因此,监听器注册的时候并没有将消息类型和监听器绑定
  • 监听器注册的代码看过了,没有绑定,那么只好去看广播消息的代码了,好在前面才看过广播的代码,印象还算深刻,再次来到SimpleApplicationEventMulticaster的multicastEvent方法:
@Override
public void multicastEvent(final ApplicationEvent event, @Nullable ResolvableType eventType) {
    ResolvableType type = (eventType != null ? eventType : resolveDefaultEventType(event));
    //根据消息类型取出对应的所有监听器
    for (final ApplicationListener<?> listener : getApplicationListeners(event, type)) {
        Executor executor = getTaskExecutor();
        if (executor != null) {
            executor.execute(() -> invokeListener(listener, event));
        }
        else {
            invokeListener(listener, event);
        }
    }
}
  • 如上述代码所示,解开我们疑问的关键点就在getApplicationListeners(event, type)这段代码了,也就是说在发送消息的时候根据类型去找所有对应的监听器,展开这个方法一探究竟:
protected Collection<ApplicationListener<?>> getApplicationListeners(
            ApplicationEvent event, ResolvableType eventType) {

    Object source = event.getSource();

    Class<?> sourceType = (source != null ? source.getClass() : null);
    //缓存的key有两个维度:消息来源+消息类型(关于消息来源可见ApplicationEvent构造方法的入参)
    ListenerCacheKey cacheKey = new ListenerCacheKey(eventType, sourceType);

    // retrieverCache是ConcurrentHashMap对象,所以是线程安全的,
    // ListenerRetriever中有个监听器的集合,并有些简单的逻辑封装,调用它的getApplicationListeners方法返回的监听类集合是排好序的(order注解排序)
    ListenerRetriever retriever = this.retrieverCache.get(cacheKey);
    if (retriever != null) {
        //如果retrieverCache中找到对应的监听器集合,就立即返回了
        return retriever.getApplicationListeners();
    }

    if (this.beanClassLoader == null ||
            (ClassUtils.isCacheSafe(event.getClass(), this.beanClassLoader) &&
                    (sourceType == null || ClassUtils.isCacheSafe(sourceType, this.beanClassLoader)))) {
        //如果retrieverCache中没有数据,就在此查出数据并放入缓存,
        //先加锁
        synchronized (this.retrievalMutex) {
            //双重判断的第二重,避免自己在BLOCK的时候其他线程已经将数据放入缓存了
            retriever = this.retrieverCache.get(cacheKey);
            if (retriever != null) {
                return retriever.getApplicationListeners();
            }
            //新建一个ListenerRetriever对象
            retriever = new ListenerRetriever(true);
            //retrieveApplicationListeners方法复制找出某个消息类型加来源类型对应的所有监听器
            Collection<ApplicationListener<?>> listeners =
                    retrieveApplicationListeners(eventType, sourceType, retriever);
            //存入retrieverCache
            this.retrieverCache.put(cacheKey, retriever);
            //返回结果
            return listeners;
        }
    }
    else {
        // No ListenerRetriever caching -> no synchronization necessary
        return retrieveApplicationListeners(eventType, sourceType, null);
    }
}
  • 上述代码解开了所有疑惑:在广播消息的时刻,如果某个类型的消息在缓存中找不到对应的监听器集合,就调用retrieveApplicationListeners方法去找出符合条件的所有监听器,然后放入这个集合;这和之前的猜测匹配度挺高的...
  • retrieveApplicationListeners方法在面对各种监听器的时候处理逻辑过于复杂,就不在这里展开了;
  • 至此,我们对广播和监听的原理已经有了较全面的认识,可以动手实战了;

开发一个自定义广播

  • 现在基于maven创建一个SpringBoot的web工程customizeapplicationevent,在工程中自定义一个发送广播的bean,在收到一个web请求时,利用该bean发出广播;
  • 创建工程customizeapplicationevent,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>customizeapplicationevent</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>
    <name>customizeapplicationevent</name>
    <description>Demo project for Spring Boot</description>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.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>
  • 自定义一个消息类型CustomizeEvent:
package com.bolingcavalry.customizeapplicationevent.event;

import org.springframework.context.ApplicationContext;
import org.springframework.context.event.ApplicationContextEvent;

/**
 * @Description : 自定义的消息类型
 * @Author : zq2599@gmail.com
 * @Date : 2018-08-16 06:09
 */
public class CustomizeEvent extends ApplicationContextEvent {
    public CustomizeEvent(ApplicationContext source) {
        super(source);
    }
}
  • 自定义广播发送者CustomizePublisher,除了用到ApplicationEventPublisher,还要用到ApplicationContext(构造CustomizeEvent对象的时候要用),所以要实现两个Aware接口:
package com.bolingcavalry.customizeapplicationevent.publish;

import com.bolingcavalry.customizeapplicationevent.event.CustomizeEvent;
import com.bolingcavalry.customizeapplicationevent.util.Utils;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.ApplicationEventPublisher;
import org.springframework.context.ApplicationEventPublisherAware;
import org.springframework.stereotype.Service;

/**
 * @Description : 自定义的广播发送器
 * @Author : zq2599@gmail.com
 * @Date : 2018-08-16 06:09
 */
@Service
public class CustomizePublisher implements ApplicationEventPublisherAware, ApplicationContextAware {

    private ApplicationEventPublisher applicationEventPublisher;

    private ApplicationContext applicationContext;

    @Override
    public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
        this.applicationEventPublisher = applicationEventPublisher;
        Utils.printTrack("applicationEventPublisher is set : " + applicationEventPublisher);
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

    /**
     * 发送一条广播
     */
    public void publishEvent(){
        applicationEventPublisher.publishEvent(new CustomizeEvent(applicationContext));
    }
}
  • 做一个controller,这样就能通过web请求来触发一次广播了:
package com.bolingcavalry.customizeapplicationevent.controller;

import com.bolingcavalry.customizeapplicationevent.publish.CustomizePublisher;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.Date;

/**
 * @Description : 收到web请求后发送一条广播
 * @Author : zq2599@gmail.com
 * @Date : 2018-08-16 06:45
 */
@RestController
public class CustomizePublishEventController {

    @Autowired
    private CustomizePublisher customizePublisher;

    @RequestMapping("/publish")
    public String publish(){

        customizePublisher.publishEvent();

        return "publish finish, "
                + new Date();
    }
}
  • 自定义广播的代码已经完成了,不过现在即使把消息发出去了也不能验证是否发送成功,先不要运行工程,接下来把自定义消息监听也做了吧;

开发两个自定义监听器

  • 我们要做两个自定义监听器;
  • 第一个监听类在泛型中定义的类型是ApplicationEvent,即接收所有广播消息;
package com.bolingcavalry.customizeapplicationevent.listener;

import com.bolingcavalry.customizeapplicationevent.util.Utils;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Service;

/**
 * @Description : 自定义的系统广播监听器,接收所有类型的消息
 * @Author : zq2599@gmail.com
 * @Date : 2018-08-15 14:53
 */
@Service
public class AllEventListener implements ApplicationListener<ApplicationEvent>{

    @Override
    public void onApplicationEvent(ApplicationEvent event) {
    //为了便于了解调用栈,在日志中打印当前堆栈
        Utils.printTrack("onApplicationEvent : " + event);
    }
}
  • 第二个监听类在泛型中定义的类型是CustomizeEvent,即只接收CustomizeEvent类型的消息;
package com.bolingcavalry.customizeapplicationevent.listener;

import com.bolingcavalry.customizeapplicationevent.event.CustomizeEvent;
import com.bolingcavalry.customizeapplicationevent.util.Utils;
import org.springframework.context.ApplicationEvent;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Service;

/**
 * @Description : 自定义的系统广播监听器,只接受CustomizeEvent类型的消息
 * @Author : zq2599@gmail.com
 * @Date : 2018-08-15 14:53
 */
@Service
public class CustomizeEventListener implements ApplicationListener<CustomizeEvent>{

    @Override
    public void onApplicationEvent(CustomizeEvent event) {
    //为了便于了解调用栈,在日志中打印当前堆栈    
        Utils.printTrack("onApplicationEvent : " + event);
    }
}
  • 把工程运行起来,先见到CustomizePublisher被注入ApplicationEventPublisher对象的日志,然后看到AllEventListener收到广播后打印的日志,如下所示,可通过日志中的堆栈信息印证我们之前看过的广播监听相关源码:
2018-08-16 18:35:15.656  INFO 7864 --- [           main] c.b.c.util.Utils                         : applicationEventPublisher is set : org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@37e547da: startup date [Thu Aug 16 18:35:14 CST 2018]; root of context hierarchy
************************************************************
java.lang.Thread.getStackTrace() 1,556 <-
com.bolingcavalry.customizeapplicationevent.util.Utils.printTrack() 25 <-
com.bolingcavalry.customizeapplicationevent.publish.CustomizePublisher.setApplicationEventPublisher() 27 <-
org.springframework.context.support.ApplicationContextAwareProcessor.invokeAwareInterfaces() 114 <-
org.springframework.context.support.ApplicationContextAwareProcessor.postProcessBeforeInitialization() 96 <-
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsBeforeInitialization() 416 <-
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean() 1,691 <-
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean() 573 <-
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean() 495 <-
org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0() 317 <-
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton() 222 <-
org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean() 315 <-
org.springframework.beans.factory.support.AbstractBeanFactory.getBean() 199 <-
org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate() 251 <-
org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency() 1,135 <-
org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency() 1,062 <-
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject() 583 <-
org.springframework.beans.factory.annotation.InjectionMetadata.inject() 91 <-
org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues() 372 <-
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean() 1,341 <-
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean() 572 <-
org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean() 495 <-
org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0() 317 <-
org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton() 222 <-
org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean() 315 <-
org.springframework.beans.factory.support.AbstractBeanFactory.getBean() 199 <-
org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons() 759 <-
org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization() 869 <-
org.springframework.context.support.AbstractApplicationContext.refresh() 550 <-
org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh() 140 <-
org.springframework.boot.SpringApplication.refresh() 762 <-
org.springframework.boot.SpringApplication.refreshContext() 398 <-
org.springframework.boot.SpringApplication.run() 330 <-
org.springframework.boot.SpringApplication.run() 1,258 <-
org.springframework.boot.SpringApplication.run() 1,246 <-
com.bolingcavalry.customizeapplicationevent.CustomizeapplicationeventApplication.main() 10
************************************************************
2018-08-16 18:35:15.732  INFO 7864 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-08-16 18:35:15.875  INFO 7864 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@37e547da: startup date [Thu Aug 16 18:35:14 CST 2018]; root of context hierarchy
2018-08-16 18:35:15.919  INFO 7864 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/publish]}" onto public java.lang.String com.bolingcavalry.customizeapplicationevent.controller.CustomizePublishEventController.publish()
2018-08-16 18:35:15.924  INFO 7864 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2018-08-16 18:35:15.925  INFO 7864 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.servlet.error.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2018-08-16 18:35:15.945  INFO 7864 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-08-16 18:35:15.946  INFO 7864 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-08-16 18:35:16.059  INFO 7864 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-08-16 18:35:16.069  INFO 7864 --- [           main] c.b.c.util.Utils                         : onApplicationEvent : org.springframework.context.event.ContextRefreshedEvent[source=org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@37e547da: startup date [Thu Aug 16 18:35:14 CST 2018]; root of context hierarchy]
************************************************************
java.lang.Thread.getStackTrace() 1,556 <-
com.bolingcavalry.customizeapplicationevent.util.Utils.printTrack() 25 <-
com.bolingcavalry.customizeapplicationevent.listener.AllEventListener.onApplicationEvent() 18 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener() 172 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener() 165 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent() 139 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 400 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 354 <-
org.springframework.context.support.AbstractApplicationContext.finishRefresh() 888 <-
org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh() 161 <-
org.springframework.context.support.AbstractApplicationContext.refresh() 553 <-
org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh() 140 <-
org.springframework.boot.SpringApplication.refresh() 762 <-
org.springframework.boot.SpringApplication.refreshContext() 398 <-
org.springframework.boot.SpringApplication.run() 330 <-
org.springframework.boot.SpringApplication.run() 1,258 <-
org.springframework.boot.SpringApplication.run() 1,246 <-
com.bolingcavalry.customizeapplicationevent.CustomizeapplicationeventApplication.main() 10
************************************************************
2018-08-16 18:35:16.094  INFO 7864 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2018-08-16 18:35:16.096  INFO 7864 --- [           main] c.b.c.util.Utils                         : onApplicationEvent : org.springframework.boot.web.servlet.context.ServletWebServerInitializedEvent[source=org.springframework.boot.web.embedded.tomcat.TomcatWebServer@1c25b8a7]
************************************************************
java.lang.Thread.getStackTrace() 1,556 <-
com.bolingcavalry.customizeapplicationevent.util.Utils.printTrack() 25 <-
com.bolingcavalry.customizeapplicationevent.listener.AllEventListener.onApplicationEvent() 18 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener() 172 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener() 165 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent() 139 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 400 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 354 <-
org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh() 164 <-
org.springframework.context.support.AbstractApplicationContext.refresh() 553 <-
org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh() 140 <-
org.springframework.boot.SpringApplication.refresh() 762 <-
org.springframework.boot.SpringApplication.refreshContext() 398 <-
org.springframework.boot.SpringApplication.run() 330 <-
org.springframework.boot.SpringApplication.run() 1,258 <-
org.springframework.boot.SpringApplication.run() 1,246 <-
com.bolingcavalry.customizeapplicationevent.CustomizeapplicationeventApplication.main() 10
************************************************************
2018-08-16 18:35:16.099  INFO 7864 --- [           main] b.c.CustomizeapplicationeventApplication : Started CustomizeapplicationeventApplication in 2.098 seconds (JVM running for 3.161)
2018-08-16 18:35:16.101  INFO 7864 --- [           main] c.b.c.util.Utils                         : onApplicationEvent : org.springframework.boot.context.event.ApplicationStartedEvent[source=org.springframework.boot.SpringApplication@77b7ffa4]
************************************************************
java.lang.Thread.getStackTrace() 1,556 <-
com.bolingcavalry.customizeapplicationevent.util.Utils.printTrack() 25 <-
com.bolingcavalry.customizeapplicationevent.listener.AllEventListener.onApplicationEvent() 18 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener() 172 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener() 165 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent() 139 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 400 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 354 <-
org.springframework.boot.context.event.EventPublishingRunListener.started() 97 <-
org.springframework.boot.SpringApplicationRunListeners.started() 72 <-
org.springframework.boot.SpringApplication.run() 337 <-
org.springframework.boot.SpringApplication.run() 1,258 <-
org.springframework.boot.SpringApplication.run() 1,246 <-
com.bolingcavalry.customizeapplicationevent.CustomizeapplicationeventApplication.main() 10
************************************************************
2018-08-16 18:35:16.103  INFO 7864 --- [           main] c.b.c.util.Utils                         : onApplicationEvent : org.springframework.boot.context.event.ApplicationReadyEvent[source=org.springframework.boot.SpringApplication@77b7ffa4]
************************************************************
java.lang.Thread.getStackTrace() 1,556 <-
com.bolingcavalry.customizeapplicationevent.util.Utils.printTrack() 25 <-
com.bolingcavalry.customizeapplicationevent.listener.AllEventListener.onApplicationEvent() 18 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener() 172 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener() 165 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent() 139 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 400 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 354 <-
org.springframework.boot.context.event.EventPublishingRunListener.running() 103 <-
org.springframework.boot.SpringApplicationRunListeners.running() 78 <-
org.springframework.boot.SpringApplication.run() 346 <-
org.springframework.boot.SpringApplication.run() 1,258 <-
org.springframework.boot.SpringApplication.run() 1,246 <-
com.bolingcavalry.customizeapplicationevent.CustomizeapplicationeventApplication.main() 10
************************************************************
  • 在浏览器输入地址:http://localhost:8080/publish,触发一次CustomizeEvent类型的消息广播,日志显示CustomizeEventListener和AllEventListener都收到了消息,如下:
2018-08-16 18:44:18.879  INFO 7864 --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring FrameworkServlet 'dispatcherServlet'
2018-08-16 18:44:18.880  INFO 7864 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization started
2018-08-16 18:44:18.912  INFO 7864 --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : FrameworkServlet 'dispatcherServlet': initialization completed in 32 ms
2018-08-16 18:44:18.958  INFO 7864 --- [nio-8080-exec-1] c.b.c.util.Utils                         : onApplicationEvent : com.bolingcavalry.customizeapplicationevent.event.CustomizeEvent[source=org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@37e547da: startup date [Thu Aug 16 18:35:14 CST 2018]; root of context hierarchy]
************************************************************
java.lang.Thread.getStackTrace() 1,556 <-
com.bolingcavalry.customizeapplicationevent.util.Utils.printTrack() 25 <-
com.bolingcavalry.customizeapplicationevent.listener.AllEventListener.onApplicationEvent() 18 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener() 172 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener() 165 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent() 139 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 400 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 354 <-
com.bolingcavalry.customizeapplicationevent.publish.CustomizePublisher.publishEvent() 39 <-
com.bolingcavalry.customizeapplicationevent.controller.CustomizePublishEventController.publish() 24 <-
sun.reflect.NativeMethodAccessorImpl.invoke0() -2 <-
sun.reflect.NativeMethodAccessorImpl.invoke() 62 <-
sun.reflect.DelegatingMethodAccessorImpl.invoke() 43 <-
java.lang.reflect.Method.invoke() 498 <-
org.springframework.web.method.support.InvocableHandlerMethod.doInvoke() 209 <-
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest() 136 <-
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle() 102 <-
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod() 877 <-
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal() 783 <-
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle() 87 <-
org.springframework.web.servlet.DispatcherServlet.doDispatch() 991 <-
org.springframework.web.servlet.DispatcherServlet.doService() 925 <-
org.springframework.web.servlet.FrameworkServlet.processRequest() 974 <-
org.springframework.web.servlet.FrameworkServlet.doGet() 866 <-
javax.servlet.http.HttpServlet.service() 635 <-
org.springframework.web.servlet.FrameworkServlet.service() 851 <-
javax.servlet.http.HttpServlet.service() 742 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 231 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.apache.tomcat.websocket.server.WsFilter.doFilter() 52 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.RequestContextFilter.doFilterInternal() 99 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal() 109 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal() 93 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal() 200 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.apache.catalina.core.StandardWrapperValve.invoke() 198 <-
org.apache.catalina.core.StandardContextValve.invoke() 96 <-
org.apache.catalina.authenticator.AuthenticatorBase.invoke() 493 <-
org.apache.catalina.core.StandardHostValve.invoke() 140 <-
org.apache.catalina.valves.ErrorReportValve.invoke() 81 <-
org.apache.catalina.core.StandardEngineValve.invoke() 87 <-
org.apache.catalina.connector.CoyoteAdapter.service() 342 <-
org.apache.coyote.http11.Http11Processor.service() 800 <-
org.apache.coyote.AbstractProcessorLight.process() 66 <-
org.apache.coyote.AbstractProtocol$ConnectionHandler.process() 800 <-
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun() 1,471 <-
org.apache.tomcat.util.net.SocketProcessorBase.run() 49 <-
java.util.concurrent.ThreadPoolExecutor.runWorker() 1,142 <-
java.util.concurrent.ThreadPoolExecutor$Worker.run() 617 <-
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run() 61 <-
java.lang.Thread.run() 745
************************************************************
2018-08-16 18:44:18.964  INFO 7864 --- [nio-8080-exec-1] c.b.c.util.Utils                         : onApplicationEvent : com.bolingcavalry.customizeapplicationevent.event.CustomizeEvent[source=org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@37e547da: startup date [Thu Aug 16 18:35:14 CST 2018]; root of context hierarchy]
************************************************************
java.lang.Thread.getStackTrace() 1,556 <-
com.bolingcavalry.customizeapplicationevent.util.Utils.printTrack() 25 <-
com.bolingcavalry.customizeapplicationevent.listener.CustomizeEventListener.onApplicationEvent() 19 <-
com.bolingcavalry.customizeapplicationevent.listener.CustomizeEventListener.onApplicationEvent() 14 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener() 172 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener() 165 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent() 139 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 400 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 354 <-
com.bolingcavalry.customizeapplicationevent.publish.CustomizePublisher.publishEvent() 39 <-
com.bolingcavalry.customizeapplicationevent.controller.CustomizePublishEventController.publish() 24 <-
sun.reflect.NativeMethodAccessorImpl.invoke0() -2 <-
sun.reflect.NativeMethodAccessorImpl.invoke() 62 <-
sun.reflect.DelegatingMethodAccessorImpl.invoke() 43 <-
java.lang.reflect.Method.invoke() 498 <-
org.springframework.web.method.support.InvocableHandlerMethod.doInvoke() 209 <-
org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest() 136 <-
org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle() 102 <-
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod() 877 <-
org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal() 783 <-
org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle() 87 <-
org.springframework.web.servlet.DispatcherServlet.doDispatch() 991 <-
org.springframework.web.servlet.DispatcherServlet.doService() 925 <-
org.springframework.web.servlet.FrameworkServlet.processRequest() 974 <-
org.springframework.web.servlet.FrameworkServlet.doGet() 866 <-
javax.servlet.http.HttpServlet.service() 635 <-
org.springframework.web.servlet.FrameworkServlet.service() 851 <-
javax.servlet.http.HttpServlet.service() 742 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 231 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.apache.tomcat.websocket.server.WsFilter.doFilter() 52 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.RequestContextFilter.doFilterInternal() 99 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal() 109 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal() 93 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal() 200 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.apache.catalina.core.StandardWrapperValve.invoke() 198 <-
org.apache.catalina.core.StandardContextValve.invoke() 96 <-
org.apache.catalina.authenticator.AuthenticatorBase.invoke() 493 <-
org.apache.catalina.core.StandardHostValve.invoke() 140 <-
org.apache.catalina.valves.ErrorReportValve.invoke() 81 <-
org.apache.catalina.core.StandardEngineValve.invoke() 87 <-
org.apache.catalina.connector.CoyoteAdapter.service() 342 <-
org.apache.coyote.http11.Http11Processor.service() 800 <-
org.apache.coyote.AbstractProcessorLight.process() 66 <-
org.apache.coyote.AbstractProtocol$ConnectionHandler.process() 800 <-
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun() 1,471 <-
org.apache.tomcat.util.net.SocketProcessorBase.run() 49 <-
java.util.concurrent.ThreadPoolExecutor.runWorker() 1,142 <-
java.util.concurrent.ThreadPoolExecutor$Worker.run() 617 <-
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run() 61 <-
java.lang.Thread.run() 745
************************************************************
2018-08-16 18:44:18.995  INFO 7864 --- [nio-8080-exec-1] c.b.c.util.Utils                         : onApplicationEvent : ServletRequestHandledEvent: url=[/publish]; client=[0:0:0:0:0:0:0:1]; method=[GET]; servlet=[dispatcherServlet]; session=[null]; user=[null]; time=[66ms]; status=[OK]
************************************************************
java.lang.Thread.getStackTrace() 1,556 <-
com.bolingcavalry.customizeapplicationevent.util.Utils.printTrack() 25 <-
com.bolingcavalry.customizeapplicationevent.listener.AllEventListener.onApplicationEvent() 18 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener() 172 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener() 165 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent() 139 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 400 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 354 <-
org.springframework.web.servlet.FrameworkServlet.publishRequestHandledEvent() 1,074 <-
org.springframework.web.servlet.FrameworkServlet.processRequest() 1,005 <-
org.springframework.web.servlet.FrameworkServlet.doGet() 866 <-
javax.servlet.http.HttpServlet.service() 635 <-
org.springframework.web.servlet.FrameworkServlet.service() 851 <-
javax.servlet.http.HttpServlet.service() 742 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 231 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.apache.tomcat.websocket.server.WsFilter.doFilter() 52 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.RequestContextFilter.doFilterInternal() 99 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal() 109 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal() 93 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal() 200 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.apache.catalina.core.StandardWrapperValve.invoke() 198 <-
org.apache.catalina.core.StandardContextValve.invoke() 96 <-
org.apache.catalina.authenticator.AuthenticatorBase.invoke() 493 <-
org.apache.catalina.core.StandardHostValve.invoke() 140 <-
org.apache.catalina.valves.ErrorReportValve.invoke() 81 <-
org.apache.catalina.core.StandardEngineValve.invoke() 87 <-
org.apache.catalina.connector.CoyoteAdapter.service() 342 <-
org.apache.coyote.http11.Http11Processor.service() 800 <-
org.apache.coyote.AbstractProcessorLight.process() 66 <-
org.apache.coyote.AbstractProtocol$ConnectionHandler.process() 800 <-
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun() 1,471 <-
org.apache.tomcat.util.net.SocketProcessorBase.run() 49 <-
java.util.concurrent.ThreadPoolExecutor.runWorker() 1,142 <-
java.util.concurrent.ThreadPoolExecutor$Worker.run() 617 <-
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run() 61 <-
java.lang.Thread.run() 745
************************************************************
2018-08-16 18:44:19.392  INFO 7864 --- [nio-8080-exec-2] c.b.c.util.Utils                         : onApplicationEvent : ServletRequestHandledEvent: url=[/favicon.ico]; client=[0:0:0:0:0:0:0:1]; method=[GET]; servlet=[dispatcherServlet]; session=[null]; user=[null]; time=[19ms]; status=[OK]
************************************************************
java.lang.Thread.getStackTrace() 1,556 <-
com.bolingcavalry.customizeapplicationevent.util.Utils.printTrack() 25 <-
com.bolingcavalry.customizeapplicationevent.listener.AllEventListener.onApplicationEvent() 18 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.doInvokeListener() 172 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.invokeListener() 165 <-
org.springframework.context.event.SimpleApplicationEventMulticaster.multicastEvent() 139 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 400 <-
org.springframework.context.support.AbstractApplicationContext.publishEvent() 354 <-
org.springframework.web.servlet.FrameworkServlet.publishRequestHandledEvent() 1,074 <-
org.springframework.web.servlet.FrameworkServlet.processRequest() 1,005 <-
org.springframework.web.servlet.FrameworkServlet.doGet() 866 <-
javax.servlet.http.HttpServlet.service() 635 <-
org.springframework.web.servlet.FrameworkServlet.service() 851 <-
javax.servlet.http.HttpServlet.service() 742 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 231 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.apache.tomcat.websocket.server.WsFilter.doFilter() 52 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.RequestContextFilter.doFilterInternal() 99 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal() 109 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal() 93 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal() 200 <-
org.springframework.web.filter.OncePerRequestFilter.doFilter() 107 <-
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter() 193 <-
org.apache.catalina.core.ApplicationFilterChain.doFilter() 166 <-
org.apache.catalina.core.StandardWrapperValve.invoke() 198 <-
org.apache.catalina.core.StandardContextValve.invoke() 96 <-
org.apache.catalina.authenticator.AuthenticatorBase.invoke() 493 <-
org.apache.catalina.core.StandardHostValve.invoke() 140 <-
org.apache.catalina.valves.ErrorReportValve.invoke() 81 <-
org.apache.catalina.core.StandardEngineValve.invoke() 87 <-
org.apache.catalina.connector.CoyoteAdapter.service() 342 <-
org.apache.coyote.http11.Http11Processor.service() 800 <-
org.apache.coyote.AbstractProcessorLight.process() 66 <-
org.apache.coyote.AbstractProtocol$ConnectionHandler.process() 800 <-
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun() 1,471 <-
org.apache.tomcat.util.net.SocketProcessorBase.run() 49 <-
java.util.concurrent.ThreadPoolExecutor.runWorker() 1,142 <-
java.util.concurrent.ThreadPoolExecutor$Worker.run() 617 <-
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run() 61 <-
java.lang.Thread.run() 745
************************************************************
  • 实战完成,自定义的广播发送和监听都达到了预期;

实战源码下载

  • 本章实战的源码可以在github下载,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customizeapplicationevent下,如下图红框所示:

image.png

  • 至此,spring实战的广播与监听部分,我们通过先看源码再动手实践的方式做了比较深入的了解,希望本次实战能对你在设计进程内的消息服务时有所帮助,借助spring容器和扩展能力,设计出更加简洁高效的服务;

欢迎关注阿里云开发者社区博客:程序员欣宸

学习路上,你不孤单,欣宸原创一路相伴...
相关实践学习
日志服务之使用Nginx模式采集日志
本文介绍如何通过日志服务控制台创建Nginx模式的Logtail配置快速采集Nginx日志并进行多维度分析。
相关文章
|
2月前
|
自然语言处理 Java API
Spring Boot 接入大模型实战:通义千问赋能智能应用快速构建
【10月更文挑战第23天】在人工智能(AI)技术飞速发展的今天,大模型如通义千问(阿里云推出的生成式对话引擎)等已成为推动智能应用创新的重要力量。然而,对于许多开发者而言,如何高效、便捷地接入这些大模型并构建出功能丰富的智能应用仍是一个挑战。
133 6
|
2月前
|
缓存 NoSQL Java
Spring Boot与Redis:整合与实战
【10月更文挑战第15天】本文介绍了如何在Spring Boot项目中整合Redis,通过一个电商商品推荐系统的案例,详细展示了从添加依赖、配置连接信息到创建配置类的具体步骤。实战部分演示了如何利用Redis缓存提高系统响应速度,减少数据库访问压力,从而提升用户体验。
88 2
|
2月前
|
Java 数据库连接 Spring
【2021Spring编程实战笔记】Spring开发分享~(下)
【2021Spring编程实战笔记】Spring开发分享~(下)
29 1
|
2月前
|
设计模式 Java Spring
Spring Boot监听器的底层实现原理
Spring Boot监听器的底层实现原理主要基于观察者模式(也称为发布-订阅模式),这是设计模式中用于实现对象之间一对多依赖的一种常见方式。在Spring Boot中,监听器的实现依赖于Spring框架提供的事件监听机制。
30 1
|
2月前
|
XML Java 数据格式
Spring IOC容器的深度解析及实战应用
【10月更文挑战第14天】在软件工程中,随着系统规模的扩大,对象间的依赖关系变得越来越复杂,这导致了系统的高耦合度,增加了开发和维护的难度。为解决这一问题,Michael Mattson在1996年提出了IOC(Inversion of Control,控制反转)理论,旨在降低对象间的耦合度,提高系统的灵活性和可维护性。Spring框架正是基于这一理论,通过IOC容器实现了对象间的依赖注入和生命周期管理。
73 0
|
2月前
|
XML Java 数据库连接
【2020Spring编程实战笔记】Spring开发分享~(上)
【2020Spring编程实战笔记】Spring开发分享~
53 0
|
4月前
|
JSON Java API
解码Spring Boot与JSON的完美融合:提升你的Web开发效率,实战技巧大公开!
【8月更文挑战第29天】Spring Boot作为Java开发的轻量级框架,通过`jackson`库提供了强大的JSON处理功能,简化了Web服务和数据交互的实现。本文通过代码示例介绍如何在Spring Boot中进行JSON序列化和反序列化操作,并展示了处理复杂JSON数据及创建RESTful API的方法,帮助开发者提高效率和应用性能。
172 0
|
4月前
|
SQL Java 数据库连接
Spring Boot联手MyBatis,打造开发利器:从入门到精通,实战教程带你飞越编程高峰!
【8月更文挑战第29天】Spring Boot与MyBatis分别是Java快速开发和持久层框架的优秀代表。本文通过整合Spring Boot与MyBatis,展示了如何在项目中添加相关依赖、配置数据源及MyBatis,并通过实战示例介绍了实体类、Mapper接口及Controller的创建过程。通过本文,你将学会如何利用这两款工具提高开发效率,实现数据的增删查改等复杂操作,为实际项目开发提供有力支持。
203 0
|
Java 程序员 网络安全
spring4.1.8扩展实战之二:Aware接口揭秘
Aware.java是个没有定义任何方法的接口,拥有众多子接口,在spring源码中有多处都在使用这些子接口完成各种场景下的回调操作,当业务有需要时,我们只需创建类来实现相关接口,再声明为bean,就可以被spring容器主动回调
276 0
spring4.1.8扩展实战之二:Aware接口揭秘
|
3月前
|
SQL 监控 druid
springboot-druid数据源的配置方式及配置后台监控-自定义和导入stater(推荐-简单方便使用)两种方式配置druid数据源
这篇文章介绍了如何在Spring Boot项目中配置和监控Druid数据源,包括自定义配置和使用Spring Boot Starter两种方法。
下一篇
无影云桌面