SpringBoot Application事件监听的实现方案

先说结论

SpringBoot Application共支持6种事件监听，按顺序分别是：

1. ApplicationStartingEvent：在Spring最开始启动的时候触发
2. ApplicationEnvironmentPreparedEvent：在Spring已经准备好上下文但是上下文尚未创建的时候触发
3. ApplicationPreparedEvent：在Bean定义加载之后、刷新上下文之前触发
4. ApplicationStartedEvent：在刷新上下文之后、调用application命令之前触发
5. ApplicationReadyEvent：在调用applicaiton命令之后触发
6. ApplicationFailedEvent：在启动Spring发生异常时触发

另外：

• ApplicationRunner和CommandLineRunner的执行在第五步和第六步之间
• Bean的创建在第三步和第四步之间
• 在启动类中，执行SpringApplication.run()方法后的代码，会在第六步后执行

再上代码：

ApplicationStartingEvent

public class ApplicationStartingEventListener implements ApplicationListener<ApplicationStartingEvent> {

  @Override
  public void onApplicationEvent(ApplicationStartingEvent applicationStartingEvent) {
    System.out.println("============>>>>> applicationStartingEvent is trigged");
    System.out.println(applicationStartingEvent.getTimestamp());
    System.out.println("============>>>>> End");
  }
}

ApplicationEnvironmentPreparedEvent

public class ApplicationEnvironmentPreparedEventListener implements ApplicationListener<ApplicationEnvironmentPreparedEvent> {

  @Override
  public void onApplicationEvent(ApplicationEnvironmentPreparedEvent applicationEnvironmentPreparedEvent) {
    System.out.println("============>>>>> ApplicationEnvironmentPreparedEvent is trigged");
    System.out.println(applicationEnvironmentPreparedEvent.getTimestamp());
    System.out.println("============>>>>> End");
  }
}

ApplicationPreparedEvent

public class ApplicationPreparedEventListener implements ApplicationListener<ApplicationPreparedEvent> {

  @Override
  public void onApplicationEvent(ApplicationPreparedEvent applicationPreparedEvent) {
    System.out.println("============>>>>> applicationPreparedEvent is trigged");
    System.out.println(applicationPreparedEvent.getTimestamp());
    System.out.println("============>>>>> End");
  }
}

ApplicationStartedEvent

public class ApplicationStartedEventListener implements ApplicationListener<ApplicationStartedEvent> {

  @Override
  public void onApplicationEvent(ApplicationStartedEvent applicationStartedEvent) {
    System.out.println("============>>>>> applicationStartedEvent is trigged");
    System.out.println(applicationStartedEvent.getTimestamp());
    System.out.println("============>>>>> End");
  }
}

ApplicationReadyEvent

public class ApplicationReadyEventListener implements ApplicationListener<ApplicationReadyEvent> {

  @Override
  public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {
    System.out.println("============>>>>> applicationReadyEvent is trigged");
    System.out.println(applicationReadyEvent.getTimestamp());
    System.out.println("============>>>>> End");
  }
}

ApplicationFailedEvent

public class ApplicationFailedEventListener implements ApplicationListener<ApplicationFailedEvent> {

  @Override
  public void onApplicationEvent(ApplicationFailedEvent applicationFailedEvent) {
    System.out.println("============>>>>> ApplicationFailedEvent is trigged");
    System.out.println(applicationFailedEvent.getTimestamp());
    System.out.println("============>>>>> End");
  }
}

主启动类

@SpringBootApplication
public class SpringBootTestApplication {

  public static void main(String[] args) {
    SpringApplication springApplication = new SpringApplication(SpringBootTestApplication.class);
    springApplication.addListeners(new ApplicationEnvironmentPreparedEventListener());
    springApplication.addListeners(new ApplicationFailedEventListener());
    springApplication.addListeners(new ApplicationPreparedEventListener());
    springApplication.addListeners(new ApplicationReadyEventListener());
    springApplication.addListeners(new ApplicationStartedEventListener());
    springApplication.addListeners(new ApplicationStartingEventListener());
    springApplication.run(args);
  }
}

运行结果

Connected to the target VM, address: '127.0.0.1:62927', transport: 'socket'
============>>>>> applicationStartingEvent is trigged
============>>>>> End
============>>>>> ApplicationEnvironmentPreparedEvent is trigged
============>>>>> End

 .  ____     _      __ _ _
 /\\ / ___'_ __ _ _(_)_ __ __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/ ___)| |_)| | | | | || (_| | ) ) ) )
 ' |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::    (v2.0.3.RELEASE)

2018-11-01 14:52:35.117 INFO 2044 --- [      main] c.l.s.b.test.SpringBootTestApplication  : Starting SpringBootTestApplication on EDIANZU-ETGVGB5 with PID 2044 (D:\Code\SelfCode\SpringCloud\Test\SpringBootTest\target\classes started by Administrator in D:\Code\SelfCode\SpringCloud)
2018-11-01 14:52:35.122 INFO 2044 --- [      main] c.l.s.b.test.SpringBootTestApplication  : No active profile set, falling back to default profiles: default
============>>>>> applicationPreparedEvent is trigged
============>>>>> End
2018-11-01 14:52:35.212 INFO 2044 --- [      main] ConfigServletWebServerApplicationContext : Refreshing org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@3406472c: startup date [Thu Nov 01 14:52:35 CST 2018]; root of context hierarchy
2018-11-01 14:52:36.891 INFO 2044 --- [      main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2018-11-01 14:52:36.920 INFO 2044 --- [      main] o.apache.catalina.core.StandardService  : Starting service [Tomcat]
2018-11-01 14:52:36.920 INFO 2044 --- [      main] org.apache.catalina.core.StandardEngine : Starting Servlet Engine: Apache Tomcat/8.5.31
2018-11-01 14:52:36.925 INFO 2044 --- [ost-startStop-1] o.a.catalina.core.AprLifecycleListener  : The APR based Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: [D:\Program Files\Java\jdk1.8.0_191\bin;C:\Windows\Sun\Java\bin;C:\Windows\system32;C:\Windows;C:\Program Files (x86)\Common Files\Oracle\Java\javapath;C:\Program Files (x86)\Intel\iCLS Client\;C:\Program Files\Intel\iCLS Client\;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;C:\Program Files\ThinkPad\Bluetooth Software\;C:\Program Files\ThinkPad\Bluetooth Software\syswow64;C:\Program Files (x86)\Intel\OpenCL SDK\2.0\bin\x86;C:\Program Files (x86)\Intel\OpenCL SDK\2.0\bin\x64;D:\Program Files\Java\jdk1.8.0_191\bin;D:\Program Files\Git\cmd;D:\Program Files\apache-maven-3.5.4\bin;C:\Program Files\Intel\WiFi\bin\;C:\Program Files\Common Files\Intel\WirelessCommon\;.]
2018-11-01 14:52:37.048 INFO 2044 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]    : Initializing Spring embedded WebApplicationContext
2018-11-01 14:52:37.048 INFO 2044 --- [ost-startStop-1] o.s.web.context.ContextLoader      : Root WebApplicationContext: initialization completed in 1841 ms
2018-11-01 14:52:37.377 INFO 2044 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean : Servlet dispatcherServlet mapped to [/]
2018-11-01 14:52:37.389 INFO 2044 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean  : Mapping filter: 'characterEncodingFilter' to: [/*]
2018-11-01 14:52:37.390 INFO 2044 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean  : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2018-11-01 14:52:37.390 INFO 2044 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean  : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2018-11-01 14:52:37.390 INFO 2044 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean  : Mapping filter: 'requestContextFilter' to: [/*]
2018-11-01 14:52:37.598 INFO 2044 --- [      main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-11-01 14:52:37.857 INFO 2044 --- [      main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.web.servlet.context.AnnotationConfigServletWebServerApplicationContext@3406472c: startup date [Thu Nov 01 14:52:35 CST 2018]; root of context hierarchy
2018-11-01 14:52:37.922 INFO 2044 --- [      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)
2018-11-01 14:52:37.923 INFO 2044 --- [      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)
2018-11-01 14:52:37.973 INFO 2044 --- [      main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-11-01 14:52:37.973 INFO 2044 --- [      main] o.s.w.s.handler.SimpleUrlHandlerMapping : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2018-11-01 14:52:38.160 INFO 2044 --- [      main] o.s.j.e.a.AnnotationMBeanExporter    : Registering beans for JMX exposure on startup
2018-11-01 14:52:38.206 INFO 2044 --- [      main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2018-11-01 14:52:38.212 INFO 2044 --- [      main] c.l.s.b.test.SpringBootTestApplication  : Started SpringBootTestApplication in 3.976 seconds (JVM running for 5.088)
============>>>>> applicationStartedEvent is trigged
============>>>>> End
============>>>>> applicationReadyEvent is trigged
============>>>>> End

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