spring boot实战(第二篇)事件监听

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本文介绍了SpringBoot中四种内置事件监听机制，包括ApplicationStartedEvent、ApplicationEnvironmentPreparedEvent、ApplicationPreparedEvent及ApplicationFailedEvent，并提供了实现监听的具体步骤。

原文:http://blog.youkuaiyun.com/liaokailin/article/details/48186331

spring boot实战(第二篇)事件监听

前言

spring boot在启动过程中增加事件监听机制，为用户功能拓展提供极大的便利。

支持的事件类型四种

ApplicationStartedEvent

ApplicationEnvironmentPreparedEvent

ApplicationPreparedEvent

ApplicationFailedEvent

实现监听步骤：

1.监听类实现ApplicationListener接口
2.将监听类添加到SpringApplication实例

ApplicationStartedEvent

ApplicationStartedEvent：spring boot启动开始时执行的事件

创建对应的监听类 MyApplicationStartedEventListener.java

<code class="hljs scala has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.lkl.springboot.listener;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.slf4j.Logger;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.slf4j.LoggerFactory;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.springframework.boot.SpringApplication;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.springframework.boot.context.event.ApplicationStartedEvent;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.springframework.context.ApplicationListener;

<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
 * spring boot 启动监听类
 * 
 * <span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;">@author</span> liaokailin
 * <span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;">@version</span> $Id: MyApplicationStartedEventListener.java, v 0.1 2015年9月2日 下午11:06:04 liaokailin Exp $
 */</span>
public <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MyApplicationStartedEventListener</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ApplicationListener</span><<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ApplicationStartedEvent</span>> {</span>

    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Logger logger = LoggerFactory.getLogger(MyApplicationStartedEventListener.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span>);

    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    public void onApplicationEvent(ApplicationStartedEvent event) {
        SpringApplication app = event.getSpringApplication();
        app.setShowBanner(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>);<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// 不显示banner信息</span>
        logger.info(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"==MyApplicationStartedEventListener=="</span>);
    }
}
</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li></ul>

在该事件中可以获取到SpringApplication对象，可做一些执行前的设置.

Application.java类

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">package <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.lkl</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springboot</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

import org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springframework</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.boot</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.SpringApplication</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springframework</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.boot</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.autoconfigure</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.SpringBootApplication</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

import <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.lkl</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springboot</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.listener</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.MyApplicationStartedEventListener</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication app = new SpringApplication(Application<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.class</span>)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">; </span>
        app<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.addListeners</span>(new MyApplicationStartedEventListener())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
        app<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.run</span>(args)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
    }
}
</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li></ul>

ApplicationEnvironmentPreparedEvent

ApplicationEnvironmentPreparedEvent：spring boot 对应Enviroment已经准备完毕，但此时上下文context还没有创建。

MyApplicationEnvironmentPreparedEventListener.java

<code class="hljs avrasm has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">package <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">com</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.lkl</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springboot</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.listener</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

import java<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.util</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Iterator</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

import org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.slf</span>4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.Logger</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.slf</span>4j<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.LoggerFactory</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springframework</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.boot</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.context</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.event</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ApplicationEnvironmentPreparedEvent</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springframework</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.context</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ApplicationListener</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springframework</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.core</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.env</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.ConfigurableEnvironment</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springframework</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.core</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.env</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.MutablePropertySources</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
import org<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.springframework</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.core</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.env</span><span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.PropertySource</span><span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
 * spring boot 配置环境事件监听
 * @author liaokailin
 * @version $Id: MyApplicationEnvironmentPreparedEventListener.java, v 0.1 2015年9月2日 下午11:21:15 liaokailin Exp $
 */</span>
public class MyApplicationEnvironmentPreparedEventListener implements
                                                          ApplicationListener<ApplicationEnvironmentPreparedEvent> {
    private Logger logger = LoggerFactory<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.getLogger</span>(MyApplicationEnvironmentPreparedEventListener<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.class</span>)<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>

    @Override
    public void onApplicationEvent(ApplicationEnvironmentPreparedEvent event) {

        ConfigurableEnvironment envi = event<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.getEnvironment</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
        MutablePropertySources mps = envi<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.getPropertySources</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
        if (mps != null) {
            Iterator<PropertySource<?>> iter = mps<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.iterator</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
            while (iter<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.hasNext</span>()) {
                PropertySource<?> ps = iter<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.next</span>()<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
                logger
                    <span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.info</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"ps.getName:{};ps.getSource:{};ps.getClass:{}"</span>, ps<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.getName</span>(), ps<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.getSource</span>(), ps<span class="hljs-preprocessor" style="color: rgb(68, 68, 68); box-sizing: border-box;">.getClass</span>())<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">;</span>
            }
        }
    }

}

</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li></ul>

在该监听中获取到ConfigurableEnvironment后可以对配置信息做操作，例如：修改默认的配置信息，增加额外的配置信息等等~~~

ApplicationPreparedEvent

ApplicationPreparedEvent:spring boot上下文context创建完成，但此时spring中的bean是没有完全加载完成的。

MyApplicationPreparedEventListener.java

<code class="hljs scala has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.lkl.springboot.listener;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.slf4j.Logger;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.slf4j.LoggerFactory;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.springframework.boot.context.event.ApplicationPreparedEvent;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.springframework.context.ApplicationContext;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.springframework.context.ApplicationListener;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> org.springframework.context.ConfigurableApplicationContext;

<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
 * 上下文创建完成后执行的事件监听器
 * 
 * <span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;">@author</span> liaokailin
 * <span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;">@version</span> $Id: MyApplicationPreparedEventListener.java, v 0.1 2015年9月2日 下午11:29:38 liaokailin Exp $
 */</span>
public <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MyApplicationPreparedEventListener</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">implements</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ApplicationListener</span><<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ApplicationPreparedEvent</span>> {</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Logger logger = LoggerFactory.getLogger(MyApplicationPreparedEventListener.<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span>);

    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    public void onApplicationEvent(ApplicationPreparedEvent event) {
        ConfigurableApplicationContext cac = event.getApplicationContext();
        passContextInfo(cac);
    }

    <span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
     * 传递上下文
     * <span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;">@param</span> cac
     */</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> void passContextInfo(ApplicationContext cac) {
        <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//dosomething()</span>
    }

}
</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li></ul>

在获取完上下文后，可以将上下文传递出去做一些额外的操作。

在该监听器中是无法获取自定义bean并进行操作的。

ApplicationFailedEvent

ApplicationFailedEvent:spring boot启动异常时执行事件
MyApplicationFailedEventListener.java

<code class="hljs axapta has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">package com.lkl.springboot.listener;

import org.springframework.boot.context.event.ApplicationFailedEvent;
import org.springframework.context.ApplicationListener;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">MyApplicationFailedEventListener</span> <span class="hljs-inheritance" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">implements</span></span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ApplicationListener</span><<span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ApplicationFailedEvent</span>> {</span>

    @Override
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> onApplicationEvent(ApplicationFailedEvent event) {
        Throwable throwable = event.getException();
        handleThrowable(throwable);
    }

    <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*处理异常*/</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> handleThrowable(Throwable throwable) {
    }

}
</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li></ul>

在异常发生时，最好是添加虚拟机对应的钩子进行资源的回收与释放，能友善的处理异常信息。

在spring boot中已经为大家考虑了这一点，默认情况开启了对应的功能：

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">registerShutdownHook</span>() {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.shutdownHook == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {
            <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// No shutdown hook registered yet.</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.shutdownHook = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Thread() {
                <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {
                    doClose();
                }
            };
            Runtime.getRuntime().addShutdownHook(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.shutdownHook);
        }
    }</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li></ul>

在doClose()方法中进行资源的回收与释放。