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This article mainly introduces "what is the principle of springboot-007 startup configuration". In daily operation, I believe many people have doubts about the principle of springboot-007 startup configuration. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts of "what is the principle of springboot-007 startup configuration?" Next, please follow the editor to study!

Several important event callback mechanisms:

ApplicationContextInitializer configuration in META-INF/spring.factoriesSpringApplicationRunListener configuration, META-INF/spring.factoriesApplicationRunner only needs to be placed in the ioc container, CommandLineRunner only needs to be placed in the ioc container 1. SpringBoot startup process

Create a SpringApplication object

Public SpringApplication (ResourceLoader resourceLoader, Class... PrimarySources) {this.resourceLoader = resourceLoader; Assert.notNull (primarySources, "PrimarySources must not be null"); / / Save the main configuration class this.primarySources = new LinkedHashSet (Arrays.asList (primarySources)); / / determine whether the current project is a web application this.webApplicationType = WebApplicationType.deduceFromClasspath () / / find all the ApplicationContextInitializer configured in the META-INF/spring.factories from the classpath, and then save the setInitializers ((Collection) getSpringFactoriesInstances (ApplicationContextInitializer.class)); / / find all the ApplicationListener configured in the META-INF/spring.factories from the classpath, and then save the setListeners ((Collection) getSpringFactoriesInstances (ApplicationListener.class)); / / find the main configuration class this.mainApplicationClass = deduceMainApplicationClass () that contains the main method from multiple main configuration classes }

Run the run method

/ * * Run the Spring application, creating and refreshing a new * {@ link ApplicationContext}. * @ param args the application arguments (usually passed from a Java main method) * @ return a running {@ link ApplicationContext} * / public ConfigurableApplicationContext run (String... Args) {StopWatch stopWatch = new StopWatch (); stopWatch.start (); ConfigurableApplicationContext context = null; Collection exceptionReporters = new ArrayList (); configureHeadlessProperty (); / / find all SpringApplicationRunListener SpringApplicationRunListeners listeners = getRunListeners (args) configured in META-INF/spring.factories from the classpath; / / call back all SpringApplicationRunListener.starting () methods listeners.starting () Try {/ / encapsulate the command line parameter ApplicationArguments applicationArguments = new DefaultApplicationArguments (args); / / prepare the environment / / 1. Callback all SpringApplicationRunListener.environmentPrepared () methods after the environment has been created, indicating that the environment is ready for ConfigurableEnvironment environment = prepareEnvironment (listeners, applicationArguments); configureIgnoreBeanInfo (environment); Banner printedBanner = printBanner (environment) / / create ApplicationContext: decide whether to create the ioc of the web application or the normal ioc context = createApplicationContext (); exceptionReporters = getSpringFactoriesInstances (SpringBootExceptionReporter.class, new Class [] {ConfigurableApplicationContext.class}, context); / / prepare the context / / 1. Save environment to ioc / / 2. ApplyInitializers (): initialize () method of all ApplicationContextInitializer saved before callback / / 3. Listeners.contextPrepared (): contextPrepared () method of all SpringApplicationRunListener saved before callback / / 4. Listeners.contextLoaded (): after contextPrepared runs, call back all SpringApplicationRunListener contextLoaded () method prepareContext (context, environment, listeners, applicationArguments, printedBanner) / / Refresh container, that is, initialization of ioc container (and embedded tomcat if it is a web application) / / refreshContext (context) where all components are scanned, created, and loaded; afterRefresh (context, applicationArguments); stopWatch.stop () If (this.logStartupInfo) {new StartupInfoLogger (this.mainApplicationClass) .logStarted (getApplicationLog (), stopWatch);} / / callback all SpringApplicationRunListener.started () methods listeners.started (context) / / get all ApplicationRunner and CommandLineRunner from ioc container, and then callback / / all ApplicationRunner take precedence over all CommandLineRunner to callback callRunners (context, applicationArguments);} catch (Throwable ex) {handleRunFailure (context, ex, exceptionReporters, listeners); throw new IllegalStateException (ex);} try {listeners.running (context) } catch (Throwable ex) {handleRunFailure (context, ex, exceptionReporters, null); throw new IllegalStateException (ex);} / / after the entire SpringBoot application is launched, return ioc container return context;}

SpringBoot Startup process reference

two。 Event monitoring mechanism

Configured in META-INF/spring.factories

# SpringApplicationRunListenerorg.springframework.boot.SpringApplicationRunListener=\ com.qiang.springboot.listener.HelloSpringApplicationRunListener##ApplicationContextInitializerorg.springframework.context.ApplicationContextInitializer=\ com.qiang.springboot.listener.HelloApplicationContextInitializer

ApplicationContextInitializer

Public class HelloApplicationContextInitializer implements ApplicationContextInitializer {@ Override public void initialize (ConfigurableApplicationContext configurableApplicationContext) {System.out.println ("ApplicationContextInitializer...initialize..." + configurableApplicationContext);}}

SpringApplicationRunListener

Public class HelloSpringApplicationRunListener implements SpringApplicationRunListener {public HelloSpringApplicationRunListener (SpringApplication application, String [] args) {} @ Override public void starting () {System.out.println ("SpringApplicationRunListener...starting...");} @ Override public void environmentPrepared (ConfigurableEnvironment environment) {Object osName = environment.getSystemProperties () .get ("os.name"); System.out.println ("SpringApplicationRunListener...environmentPrepared..." + osName) @ Override public void contextPrepared (ConfigurableApplicationContext context) {System.out.println ("SpringApplicationRunListener...contextPrepared...");} @ Override public void contextLoaded (ConfigurableApplicationContext context) {System.out.println ("SpringApplicationRunListener...contextLoaded...");} @ Override public void started (ConfigurableApplicationContext context) {System.out.println ("SpringApplicationRunListener...started...") @ Override public void running (ConfigurableApplicationContext context) {System.out.println ("SpringApplicationRunListener...running...");} @ Override public void failed (ConfigurableApplicationContext context, Throwable exception) {System.out.println ("SpringApplicationRunListener...failed...");}}

Just put it in the ioc container

ApplicationRunner

@ Componentpublic class HelloApplicationRunner implements ApplicationRunner {@ Override public void run (ApplicationArguments args) throws Exception {System.out.println ("ApplicationRunner...run..." + args);}}

CommandLineRunner

@ Componentpublic class HelloCommandLineRunner implements CommandLineRunner {@ Override public void run (String... Args) throws Exception {System.out.println ("CommandLineRunner...run..." + Arrays.asList (args));}} at this point, the study of "what is the principle of springboot-007 startup configuration" is over, hoping to solve everyone's doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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